Is your SPS completly stock?
From what I hear...Wheels make a big diff especially if it spends most of it's time in the twistys. My SPS came with the magnesium rims already installed by the previous owner, so I have nothing to compare it to, and am unable to judge how much difference they actually make over stock. Also, you may want to look at the gearing, I'm running a 15/39T on mine wich really seems to be a good combo for the closer ratio gearbox.
The lightened flywheel from nichols really wakes the SPS engine up, but it's not really going to give you any more power...It'll just spool up a bit faster...but it makes it fun to ride!
If your looking for braking, slap on a set of 4 pad calipers and lines...they bolt right on, and make a huge difference! I went with the radials, so my bang for the buck ratio was severly cut down...but damn they stop nice!
Put a power commander on it...the stock chip is pretty rich and has a pretty bad flat spot in it...There again, it wont really give you anything power-wise, but it will make it more manageable.
Hope this helps a little bit.
