I beat the piss out of my 325iX for years, the only thing that ended up giving up was the M20.
I'd just add that "marginally" slower may be an understatement. My iX was chipped, 5spd, has some weight savings, etc, and it still much slower than a regular 325i.
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Hot: 2001 Estoril M RoadsterZCP 19's michelin supersports, ZHP knob, JL 8W3
Cold: 2002 TiAg M3 6mt
deoranged, dechromed, led tails, ZHP knob, UUC SS v3, GROM, OEM 18's w310's,
Fun: 2006 YZF-R6, black, ohlins, pazzo, graves