I noticed a very slight increase in mileage with my challenge xpipe but that quickly went in the tank with my tune. No one is getting 29 or 31 in these cars. Low 20s is about it if all freeway.
02 Tiag e46 M3|6MT|GC plates|MCS c.o.|GC bars|GC race control arms|GC bushings & bearings|BW eng. & tran. mounts|subframe kit|BW race shifter|BW Jaffster|Euro header|BW race|K&N c.a.i.|Epic race tune|Rouge race pulleys|Seibon CF hood|CSL bumper|ST-40|SR34|SS lines|half cage|Recaro profi|Profi 2 harness|BMWpedals|Apex studs|