Ran across these videos watching e53 X5 rally cars. Looks like quite a few teams are going with the M3 engines and kick'n ass. The cars still weigh about 4200lbs, so my *possible* S54 swap is becoming more a reality. More research to come...... until then here are some sample vids. The second vid is crazy cool.

BMW X5 Rallysprint Villariezo - YouTube

Rally sprint Villariezo 2012 X5 - YouTube

__________________
2005 X5 3.0, 6MT, Alpine White on Truffle Brown, Sport, Preim, and Cold Weather, Alpina Stainless Headers, AFe Intake, UUC SSK, OEM 87's, 3.64 Differential Swap,Performance Modified Euro 2 Tune, UUC LTW Flywheel and HD clutch, Bilstein B12 Suspension kit
Future mods ZHP/Schrick Cam Shaft upgrade, Operation code name:Doppelschrauben-Kompressor

Wife's Ride: 2011 e70 X5 351 M///Sport.

Also in the fold: 2004 X3 3.0, 6MT, Black Sapphire on Terracotta, port, Premium, Cold Weather.