Hiyay Wishmaster, having driven all of the Apex cars the BMW Z4 is easily the most consistently quick car for how I drive. All of the cars are fairly heavy understeerers on but still quick (BOP is exceptional) and unless you overdrive them, (guilty) the tyres last well too once you find a setup. Good advice as usual from Davidporeilly. Particularly for the BMW more ( meaning more negative) camber on the front will add to your problems of understeer. Do try more positive front camber settings, you might be pleasantly surprised. I find these cars are very sensitive to rebound settings and a high rebound on the front will again compound any understeer issue you may have. Good luck, they are very rewarding cars with persistence. Like all cars you can't get a good feel in 1 or 2 laps, 5+ laps is required to fine tune.