Your actual performance is unlikely to change. What will change significantly is the feel and the ride. The car will feel slightly more sluggish on turn in. Ride will definitely feel harsher over rough pavement as that extra unsprung weight bobs up and down over bumps. The extra weight on the front wheels is more concerning than on the rear in this regard. VMR has some really nice designs, but what is really the point when you adding that much weight and when there are PLENTY of other light weight options.
Audi S6 * Audi S3 * Porsche Cayman GTS
--Former BMW M3 owner