Magnaflow 2.25". I did mine closestto the engine,,.. Personally it does not matter i think its just preference maybe u can do it inthe middle leave room just incase u want to do cat downpipe to it will be easier for mechanic

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Call Me For Tires: 732-421-6931
Past
2000 E46 325i
2006 E53 4.4i Sport
2006 X5 4.8is
2011 E90 328xi
2011 E71 50i Fully Loaded :thumb up:
Current
2000 E39 528i
2013 F10 M5
2013 F10 535xi
2017 X3
2017 Sedona
2017 Optima
2016 Fiesta