I haven't done it in *this* seat, but I've done it in a bunch of other BMW seats. It's pretty easy. You just need to buy hog rings and hog ring plyers. A cheap kit off amazon is fine.

It makes a huge difference. I had to replace the passenger foam in my E90 M3 recently because the airbag sensor failed. (Yes, integrated. Yes, that was obscenely expensive.) I took advantage of that to swap the little used foam to the driver's seat while I was at it.

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2011 M3
2006 Sierra 2500HD 4WD LBZ/Allison
2004 X5 3.0i 6MT
1995 M3 S50B32
1990 325is
1989 M3 S54B32

Hers:
1989 325iX
1996 911 Turbo