No Traction...Almost Dead

[blk_frmnt]

I recently bought an AU1 Fairmont. It's been lowered slightly, and has 16in non-stock wheels. The tyres are near-new. However, driving yesterday in the wet I nearly killed myself on the corners. The back-end just slides out with out warning, even at speeds I would consider more than safe for certain corners. I've driven plently of RWD cars before, but this was the most unsettling thing ever. Is there some way to increase the traction? (Other than loading the boot full of rocks...) Maybe someone f-cked up the suspension when lowering it, causing this.

Any advice would be greatly appreciated.