Well you have the 17x9's right? That would be the best autocrossing wheel probably since it's widest...and trust me, with our heavy cars, we need the width. I will have my 275 40 17 Victoracers for sale within a week or so...they still have tread left on them...
(at least way more than yours..heh)
Anyway, if you want something firmer, I would just go with an aftermarket spring and shock combo....you can buy some 2.5 inch diameter springs (10 inch long for the front and 7 or 8 inch for the rear) and do a nice conversion. Very easy to change since you don't need a spring compressor. Also, do the rear insert conversion....much cheaper for the budget racer like us..
Koni is really the answer if you're serious about racing. (I got the yellow adjustables )...otherwise your setup seems ok . Rear sway bar is a must of course, the pillow mounts are great for camber changes.
The only real advice I can offer is add as much camber as you can on the front to increase the grip on that end...I am running over 3 degrees now and seems to be working great... But first you need good sticky wode tires. Once you stiffen up the springs, you'll be able to run 275's on the 17x9's without fender rolling..(or very minimal tuck at that)
Also, if you don't do any major body mods and brakes, you'll be able to stay in D-Street Prepared class which is a great match for our alltracs.
I am running SM and doing really well but it's a very tough competition in this particular class (unlimited turbo, boost, computer, unlimited brakes, suspension....talk about spending money. If i was to do this all over, I'd stick with DSP...oh well....it's a good challenge at least.
M.