H - Sport Springs - New Bump stops
H - Sport Control Arms - Lower
H - Sport 22 mm Sway Bar
Also going from 16" Rims to 17" at the same time

Not planning on tracking at all just street driving (I tend to drive agressive)

2003 Mini Cooper

Anything else that would be needed to take it to the next level?

 

MC can be upgraded like an MCS for suspension from mild to moderate to extreme for any use from street to show to track. Depends on your budget so what do you want to spend and what is more important-

Looks
High performance
Fitment- do things rub
Wear and maintenance
Price
Street comfort

Since the MC is not excessive on power (what power mods do you have?)
Intake? Cat back Exhaust? Heavy stereo upgrade with sound deadening?
Heavy Factory options- sunroof, HK audio

You want upgrades to tend to be less weight not more.
1.H - Sport Springs - New Bump stops
Are fine, lower your car about 1" front and rear, allow for more aggressive cornering. But when used with stock springs will tend to wear out the springs if you have a loaded down MINI- how many people do you usually have? and also if you track the car more it will wear the shocks in about a year or less- since your MC has miles on it already the stock shocks may not last too long. A common upgrade is to replace shocks at the same time especially if you have at least 30,000 miles already.
2.H - Sport Control Arms - Lower
These are OK and help to adjust rear camber to your liking. About -1.0 if you want more comfort and about -1.6 at most (more negative increases understeer relative to front camber). Alta and Helix arms are lighter but maybe a bit more noisy.
3.H - Sport 22 mm Sway Bar
This can work but most will be fine with a 19" three hole rear bar. Another option for the price is a hollow H sport 25mm Competition bar which is about 5 pounds lighter but it is also stiffer than you can make use of.
4.Also going from 16" Rims to 17" at the same time
Assuming 16" stock rims to 17" aftermarket rims? 17" stock rims are usually very heavy and not a good upgrade for most MC.
Light weight 17" about 16 lbs or less would be good but tire selection is limited to about 205/45-17, 205/40-17 if load rating is at least 84 and 215/40-17 due to lowering your MINI. 16x7 would give more flexibility on possible tires in 40, 45, or 50 series like 205/50-15 which would fit and give you some comfort for street use. If you don't care about comfort then the 40 or 45 series tire is workable.

The list of upgrades is never ending. people easily spend from $1500 to $4000 plus on suspension upgrades.

What more for suspension (since this is the suspension forum)?
Front adjustable camber plates-
Better than cheaper fixed plates they allow a range of front camber settings. Stock is -0.5 which is OK for street but not good for cornering on the track. If you really are doing only street driving you could leave it stock or get fixed plates for less but you have to use whatever camber the fixed plate allows for- might be different front right vs left. More front negative camber will wear the inside edges of the tires front or rear- not too bad but some.
Coilovers-
Can be specifically for street use- range in price about $2000. don't get the track version- it's too stiff and bumpy for street use. Bilstein PSS9 and other adjustable coilovers are popular but costly. You can set ride height- good for clearance on your wheels, set dampening and rebound for comfort- easy to do yourself, and allows for a matching set of upgrades for the shocks and springs at the same time.
Adjustable Endlinks-
On the ends of your front and rear swaybar are used to remove preload from the bars when doing corner balancing for track use, not needed for street use. Corner balancing allows for adjusting ride height to balance the weight of the car right front + left rear to = left front + right rear weight.
Front tower strut bar-
Not really needed for street use. Can stiffen the front and protect a little against deforming the top of the strut towers- M7 tower plates alone will help.

A word about wheels-
Before you buy 17" or larger think about:
Budget for both tires and wheels
Clearance for your suspension given the tire sizes that will fit the wheel
How your roads are- if lots of potholes it's risky to use bigger rims that are light- easy to damage the stiff sidewall of the tires and bend a rim unless it is very strong- which means it's either heavy or expensive.
If you drive carefully all the time and never hit road hazzards then you can use almost any wheel. Heavy wheels and tires will perform sluggishly, take longer to brake to a stop or accelerate from a standstill. Light weight on wheels and tires usually means more responsive and quick. A few pounds are not going to make that much difference but the range can be very large.

 

Current mods

CAI
CatBack
Header with lowflow cat
ECU Tune (well Unichip actually)
Iridium Plugs
Nology plug wires
New Coil pak

Rims are ASA AR1's 20.7 Pounds (Tirerack calls them Lightweight)

No stereo upgrade planned
Just me in the car
Contemplating removing spare tire and putting in some green slime and compressor.
Yes I have a sunroof
and a CVT not the 5 speed

Mostly Interstate driving so roads are fairly smooth very few bumps

 

OK on upgrades. How many miles so far? Are you original owner?
Was the car ever tracked or autocrossed in the past?

Trying to get a feel for wear on the shocks given you want to use lowering springs.

Most likely going with lowering springs is OK but considering Koni Yellow Shocks or similar would be good.

Lowering is OK but ride quality can suffer. If you want better handling and not have to fuss with less clearance but also get good ride comfort for street and daily use then Koni FSD shocks are a good option- and leave the springs stock.

I had H-sport springs and stock shocks as did others in my area used for street and autocross/track/lapping sessions. Of the three MCS in our group all gave up the H-sport and moved to Bilstein PSS9 coilovers, one made a move to Koni yellow shocks first. I felt the ride quality went from rough to jarring as time went on.

Your other mods are fine for now.

The wheels are 17x7 with +42mm offset which is at the border of clearance for H-sport springs which means you really need tires that are stock sized or smaller in tire diameter not larger or you can get some rubbing in the rear wheel arch plastic trim. Not bad but loud.

Safe tire sizes for use with lowering springs would be those I mentioned and stay away from 215/45-17 or anything taller than 24.3" tire diameter.
215/40-17 will work but often those tires are more expensive. Stock 205/45-17 makes the most sense. 205/40-17 is possible but some are lower rated than needed plus it's a small tire. Any 40 series tire is not going to ride as comfortably.

Doesn't sound like front camber plates are needed.
If you don't get lowering springs then you don't really need the rear lower adjustable control arms.

If you do get the Koni FSD shocks then a 19mm rear adjustable sway bar would be a good match.

For H sport springs either 19 or 22mm rear bar would be ok. for the MC I favor the 19mm bar because you can use all three holes while with the stiffer 22mm bar you'd likely use the softest or middle setting only.

 

40k miles I am second owner the car has had no track time at all. The person that owned it before only had a passenger for about 20 miles the passenger seat is pristine.

I think I am leaning toward not lowering at this point after reading many more posts here and elsewhere I love the look but as I do drive quite a bit I dont want to be a MINI Milkshake...

So I may just lean toward the 19" Sway Bar

Thanks for the Tips

If you have any more please let me know as I am fairly new to changing anything on a car.

 

I think that you two have this thread pretty well covered.

 

You might start with-
19 mm 3 hole adjustable rear sway bar
Good sticky Tires to fit your 17" wheels
Try looking at Ultra High Performance summer tires (not for snow)
215/45-17 would be good.
Maybe General Exclaim UHP since that gives lighter weight, good comfortable ride and good handling at lower price. If you want your tires to last a longer time then consider All Season Ultra High Performance tires. Maybe Kumho Ecsta ASX.

 

D3MON Minihune gave great advice about H-sport 25.5mm "comp" bar, KONI Sport shocks and good tires to add to your package I went from run flats to Hankook sports K something I forgot in stock size, but definatley better. And now Falken Azenis Rt615 in 215/40-17 which are amazing but wear kinda fast.