You won't find any issues. I don't see the benefit of going with anyone BUT ESS. They have had zero failures, offer some of the highest hp kits on the market and their customer support is the best!
E92 M3 DCT...Powered by ESS VT2 650 Aquamist HFS-3
CURRENT WORLD RECORD HOLDER 1/4 MILE - 12/7/12 (ESS VT2 625, Meth Off)
ATCO RACEWAY: 10.65 @ 131.79MPH 1.725 60FT