My brother drives a 57 plate LWB 318CDI V6 Sprinter and that has been remapped to 230BHP, it flies and i know some cars have trouble keeping up never mind Transits!
I've had 3 transits myself in the past until i brought a 316cdi Merc in 2003. Had that remapped and since then always had a Sprinter as an owner Driver. Reliability/Performance and Build Quality won it for me which the Transit lacks in my opinion.