If money was not a problem when considering the 550i or the 535 I would go with the 550i all day. These are small things, but I enjoyed driving the 550 more at the BMW Performance center over the 535. The TT V8 was quick and moved out fast. The 535 is quick as well, but didn't give that feeling as much as the 550. I also like the exhaust tips better on the 550, but that is just a small detail.