I've got 79000 on my X5. Like I said, I put it off for more than a year. Axle fluid had been changed at the 30K service but with BMW fluid because that's all the dealer would put in. Normally I like to drain and fill all drivetrain fluids every 2 years or 30K miles because I tow with it. With the new trans in it, I'll do a trans service at the end of every track season to keep the trans healthy.

Yes, my ex (ex-wife which is far more expensive than an ex-gf) knows about chipping. She used to track a 944, then my previous 911. Her Audis were always chipped, and she can adjust her own sway bars to dial in understeer or oversteer depending on the track. And when I get my current 911 back together with the new cage, and 100 more hp with the engine I'm building, I'll let her take it out a few times too. And FWIW, both of my sisters track their own 911's and drive modified street cars too, one of them a 135 sport.

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'04 E53, 4.4 Sport
'97 E39 528i
'86 911 Carrera, track car
'96 BMW R1100R