So I have some Christmas money that I want to spend on my mini. I've wanted a set of 4 point belts for more than 10 years so that's near the top of the list but I've also been considering a stiffer rear sway bar and maybe an under chassis brace. I could also go for a good tune

My car is an 03 R53 with a 17% pulley, Alta intake, m7 strut brace, m7 occ, stock tune, stock suspension. It's my daily driver but I do like to hit the track a couple of times a year. I'll probably be replacing the struts and lca bushing before too long and maybe putting on I.E. fixed camber plates but that's more of maintenance. This purchase is for fun. I'm really leaning towards belts just because I've wanted them for so long but they seem a little silly.

 

The rear sway bar is going to be the best bang for the buck. The Schroth quick fits are nice, but they really only show benefit when you're pushing the car (at the track) whereas a sway bar is going to show benefit every time you turn.

I have a set of quick fits and they have been out of the car since I left Dragon last year, they became too much to deal with in a daily driver for me, but they do make a world of difference when you push the car.

You'll notice you're more stable as a driver due to not having to hold yourself up on the steering wheel and not having to keep balance with your legs, there is a noticeable change in your driver ability with them in.

But I still 100% encourage the purchase of a larger rear sway bar.

H-Sport 25mm Comp Sway Bar

Schroth Quick Fit Harness

 

I'd say Powerflex bushings HERE and a rear sway bar HERE (I run Whiteline bars on my car) are what I would recommend.

 

get both from the market place, typically you get can single harness for 120$ used or 200 for both. and then the RSB from whomever you wish to order from. these are very rare on selling used

 

1. 22mm or larger rear swaybar

2. Metal coolant reservoir

3. Cravenspeed metal dipstick

 

Rear Sway Bar and Shorter/Stiffer Springs.

You can get TSW Rear Bar and TSW Springs for $410.

Changing springs makes sense since you plan to do struts.
The size of the rear sway bar depends on a few things but mainly on whether or not you are going to do camber plates (which I highly recommend). Since you plan to do camber plates, a 19mm bar would be a good choice.

If you lower your 2003 R53 there is no rear camber adjustment so eventually you will probably want to purchase a set of adjustable rear lower control arms. If you want to get adj lower control arms within you $400 budget, look for used sway bar and maybe even used springs (without too many miles). People do sell these used when they upgrade to a different suspension setup, such as coilovers and 25mm bar.