my car has coilovers, but is lowered extensively on 17x9's. there is no grip in the wet, but superb cornering in the dry. if you check your rear camber, u will see why, mine is ridiculous. get some camber correction in the rear, then try again.
if your tyres have massive blocks they just wont move the water out, mine are like this and it is dangerous at any speed toi enter a roundabout in the wet. i try not to drive much in the wet unless i have too. if you ant wet grip, lose the blocks.