Whats up guys. Im planning to add X Pipe for my Eisenmann exhaust. Planning to cut the stock resonator in the mid section, and weld this magnaflow Tru X Pipe. They have three different inlet diameter sizes. Which are 2.25, 2.5, and 3. I have 535i and not sure which inlet diameter should I go for. If you guys know which diameter I have to use, could you please let me know. Thanks for ur help all.