im losing grip, help

[galvatron]

i recently baught a set of 17s and had my car lowered 40mm on just springs with original shocks. i believe the tracking maybe out, but i had 2 flat tyres recently and put the wrong psi in then 34 in them.
 Do 17s just not drive aswell as 15s? the tyres seem good it just feels like its got a mind of its own:(
mike

[Overseer]

i've heard that the larger / lower profile you go the more likely the car is to 'tramline' along things like seams in the road, and that of course due to less air the ride is a bit harsher.

don't know this from experience though as i'm still running the stock 15's

[davero]

when i bought mine, it was lowered on 17's, it was harsh and it tramlined all the time. The car now has a bilstein setup at approx. factory height and 16' anniversaries, you would not beleive the difference