i installed racing springs on my gf's chevy cavalier a few months ago.  the ride and handling is great but sometimes it feels as if the struts are "bottoming out". any detailed suggestions???  

did you install any shocks and struts with them?  first get something like koni reds or yellows, then when you install them cut about 1" off the bumpstops to give the dampers more travel.  

so would i want to get shorter struts?  

What your dealing with is body roll. You have to deal with the cars natural want to flex. Struts can help to deal with the flexing.  

i dont think thats it.  it sounds like he put lowering springs on stock struts, and the struts have worn out.  he now smacks every bump hard.

yeah, you'll want a strut/shock that is physically shorter, one that was made specifically for a lowering spring.