I'm one month into owning an 05' MCS (137k miles) and was looking into a few mods. Not knowing the history of the car, I really wanted to cautiously stage my Maintenance and Mods. I ask that you take a peek at my list and make any suggestions:

1. Valve cover gasket and oil change [Done}
2. Spark Plugs [Done]
3. Air Filter [Done]
[4.] Clutch Job including task 4 through 7 along with rear main seal
4. Supercharger Oil change ???
5. Pulley Upgrade with Front seal (17% Reduction)
6. Harmonic Balancer
7. Motor Mount upgrades ???
8. Control Arm and Ball joint

Feel free to chime in with any recommendations.

 

that is a good list. Some comments:

oil: use good synthetic (mobile1, royal purple, amzoil, etc.), change it it every 5000 mi., NEVER let it run low
air filter: a good performance cold air intake helps out the MINI as the stock air box is restrictive
clutch: the stock flywheel is a dual mass setup that tends to fail, prolly want to replace that while you are in there
supercharge oil: some people change it, some people say leave it alone. i changed mine.
17% pulley: recommended
harmonic balancer: definitely change this. failure item.
motor mounts: if it hasn’t been changed already, your upper passenger side mount is bad. change it. the other ones are probably okay. upgrade them if you want; makes the feel of the car much harsher
control arm bushings: lower control arm bushings are another known failure item. if yours havent been changed, they are shot. have poly bushings in the lower control arms and have the alignment done, you will love the feel of the steering

also: ditch the run flat tires for some good performance tires. lightweight wheels are a bonus, too
dont know it your MCS is a manual trans. put redline MTL in the 6 speed. if its an auto, i’m not sure what the best plan is for it, but there are many threads here about it.

good luck!

 

With that mileage for sure do the powerflex control arm bushings. And that would overlap in labor with your clutch job as you pull the subframe.
Valeo kit for the clutch is great
http://waymotorworks.com/valeo-clutc...l-kit-r53.html

Harmonic balancers fail daily so go to an ATI Damper will be a mod and preventive. http://waymotorworks.com/super-dampe...ulley-r53.html
While doing that it's a good idea to do the timing chain as we find over 130k they are stretched, and the plastic guides with the age are now prone to cracking.
http://waymotorworks.com/timing-chai...0-r52-r53.html

If you plan to do a supercharger pulley that would overlap with the chain as you pull the tensioner to get the front cover off

good time for a fuel filter as we normally do them at 100k
http://waymotorworks.com/fuel-filter...0-r53-r52.html

 

That's a good list and what Way suggests is great advice. However, I would first recommend making sure of the state of your engine. A compression test, a leak down test and an oil analysis before you sink a lot of money into your car...and then finding out that you have more serious problems.

 

For a car this mileage, I would not go nuts with drivetrain mods. It it were me I will take 15% pulley over 17% for reliability rather than bragging right.

Do tread cautiously with engine mounts. Stiffer does not translate to better if you care about NVH which you have to live with daily. For a road car, driveability is the most important. There is benefit with doing the mods one step at a time so you will know the effect, positive or negative.

 

I love my 17% pulley. Builds boost faster and at a lower rpm than the 15%....which is perfect for the street. As far as reliability......you never hear of anyone having issues with 17% pulleys.....maybe the 19% ones if you track them.