I have an RS3 8v with 6000 miles on the clock. I had the MTM engine upgrade fitted about 1000 miles ago which raised the BHP to 422. The 0-62mph time is slightly faster but the mid range acceleration is significantly quicker. Also, the top speed has been electronically limited to 182mph as the standard tyres are only rated up to 184mph. All my Audi's since 1983 have had engine upgrades with no electrical or mechanical problems.