I assume you are talking about springs? From the spring selections available I'm using relatively light LOSI and Associated springs or heavy TEKNO springs in the rear. Check the TEKNO SCT410 thread. A very helpful fellow has put together a list of front and rear springs from many different sources and put them in order by spring rating. I printed this and take it everywhere. Since you said your chassis isn't slapping the ground much you are probably running much heavier rear springs than me (or have a flatter track). I don't have LOSI cars so my spring selection won't help you but I think you said you have three different LOSI springs, I count seven LOSI rear spring rates ranging from 2.50 to 4.30 (6 front spring rates). If you don't know the spring ratings of your springs check out the list I referenced. The heaviest rear spring I use in any of my cars is 3.55 in my 1/8th scale buggy.