Well the 535 is very responsive. I am pretty happy with mine, have you driven the 535i yet? If you do and you like it, then don't even bother driving the 550.
Originally Posted by denniscasey
Just looking at responsiveness, don't forget Torque: 295 at 1500-5000rpm for 535 and 442 at 1750 to 4500 for 550.
2013 535i Space Grey, Biege, M-SPort, Premium, Tech, Cold Weather, Luxury Seating, PDC, 6MT ED-10/11/2012 - PCD Redelivery-12/14/12