There is a used vf540 and Ess 535 for sale for approx 6k. Easy self install plus 1k for tune. Last 1k I would do test pipes and ACM exhaust mod. Stock suspension, tires and brakes are more than capable to handle the power. Keep the car stock looking and you will have one hell of a sleeper!
E92 M3 DCT...Powered by ESS VT2 650/DCT GTS Software/Aquamist HFS-3 50/50/Morr /Toyo R888's
ATCO RACEWAY: 10.65 @ 131.79MPH 1.725 60FT
(Stock ESS 625)