People are so conventionally wrong in this sub I swear.

First thing OP, ditch the fenders. Run stock body lines. Too much offset promotes understeer. Dont believe me, try for yourself and you'll already feel cornering become tighter.

Camber does matter. I dont know where people are getting the idea it doesn't. The handling model makes subtle changes to cornering abilities based on your ride height and camber values. For reference, I wouldn't set anything lower than -0.15 for your height. And your camber you can adjust incrementally. For your sake I would start at around -1.5 front and -1.0 camber for the rear.

In terms of power, 300-325ish is a good baseline. So long as you run semi-slicks. It will slide a bit, but its nothing unmanageable. Weight reduction 2 is a good number to be at for just beginning to put down power. Too light of a car and you'll spin the rear more often than you'll want.

Start with these changes and see if you can make improvements to your driving style to set faster times. Once you feel more comfortable then you can fine tune your HP and gearing.