Same exact engine in the 535, but it does weigh a little more. This will slow down launches compared to the 1 and 3 series.
What's nice about the twin scroll single turbo is that power keeps building right up to redline, similar to an M5 but more powerful. It sounds like a friggin jet engine taking off. There are clips on Youtube.
RB turbos are cheaper and based on the stock assemblies. You trade in your existing and they send you the larger ones. They add about 100 hp. Fully modded with tune, downpipes, FMIC, meth etc, that's how you see 500 hp to the wheels. Add around 20% to get BHP at the crank. Cost is $3,200 plus another grand for installation.
I heard the single is more expensive but haven't seen numbers. I have plenty power for my needs.
Look at about 6 minute mark:
Audio: Jehnert Flatline speakers, Mobridge M1000 DA2 prepro, Helix P-DSP, Zapco Z-150.6 amp, iDock on dash
Performance: Protuned Cobb, AR Downpipes, ER FMIC/CP, DCI, RB turbos, KW V2 coilovers, AEM 320E LPFP/ported fuel rail
Last edited by Oceans10; 01-29-2013 at 08:04 AM.