Just getting used to the 09 S enough to find out how it behaves at the limits.
I feel it gets a little "jiggley" out back in entrance to a quick mid-speed corner. RunFlats? Never had them before. It will hop when going over an expansion joint on an on ramp quickly. Thinking about putting on conventional tires.

Second I don't like is how touchy and grabby the brakes are. If you have to hit them quick but lightly, they will grab. Overall petal is much lighter than I am used to. Thinking HPS pads maybe.

Not as quick as my RSX. Not enough tire for a start. I have the 195 17's. 205 or 215's may suit it better. Any issues with something like 960's is that size? Does it tent to follow the road irregularities too much.

I was considering dropping it an inch, but I see BMW seems to have so underengineered the CV's, that may not be a good idea. But isn't the works lower? An inch lower and maybe Koni golds may make a nice street setup. But I do love my KW's on my RSX after I found the correct spring rates.

Any way to make it directionally more stable under hard acceleration? Yea, I know the weight transfer and all, but it is a tad squirreley. I don't know how normal this is as I have never had a FWD that was this quick before.

 

I would say:

You can't go wrong with Hawk Pads. I have had them on several cars and love the feel.

Run-Flats attribute a lot to any semblance on poor handling with your mini. Ditch them in favor of a good tire. I run the Hankook RS2 and I love them. Great for the summer or the year round arid climate of a desert. Nice and grippy with a decent tread life.

Lowering the car would def. be a good start. I went with the Texas Speedwerks springs and they provide great feedback. Also, a rear sway bar upgrade would add some neutrality to your handling package.

After you perform these changes, I think you will really love the way your mini cooper feels!

 

+1 on Hawk HP or HP+ pads just HP if you don't track your Mini.
+1 on the TSW springs. More improvement can be found with Koni yellows
+1 on the rear sway bar.

Do all this and you will forget about the RSX and your decision to go Mini will be well remembered!

BTW +1 on ditching the runflats. I have a dedicated track set of wheels so my BFG G-force sport daily drivers are what some would consider on the hard side at a 340 tread wear. I'm still able to pull over 1 lateral G with them on the skidpad so there is performance in them. this tire is not a compromised tire it's what I found that will last for over 40K miles yet can perform. There are longer lasting (but the performance drops off quickly) and better performing (but they wear out quickly and the excessive heat cycling reduces the adhesion of the rubber to the pavement) so tire choice is truely what you are needing.

GL with the improvements