Definatly a 335i... sourcing out a particular colour combo and options... I did a side by side comparison between a Dinan Stage 3 (maybe 2 can't remember exactly) 335i and a 2011 M3, and I was shocked and happy I don't need to spend $100K on a new M3...
335i is a monster if tuned correctly... I have complete faith in you! Make the tune hidden and unchangable by the dealer... it will sell like hotcakes!