Can some one help me please.

[Leelosi]

Hi I have gone from a Dave to a superstox and I just seem to be at least a lap of the pace now. Every time I hit a corner with a bit of power or speed my car seem to snatch or kind of slow right down half way through the corner. Please help as I can't lose again I have the tuning springs diff and independent front wishbone set., also what is that nice looking motor spacer for....? Thanks for the help if anyone can cheers lee