I'd like to know the answer to this too. I'm looking at these cars, and I don't know what the right move is.
With most cars, I'd forego the warranty, as I'm pretty sure I could fix most problems that arise, myself. But the Bimmer, along with the repair costs, intimidates me a bit.
So I'll wait with you, for an educated response.
Corvette guy, mostly lurking. Love non-Bangle Bimmers.
77 C3 Corvette, Corvette Light Blue on Smoke Leather
355ci balanced and blueprinted, GMPP Vortec Heads, Keith Black flat top pistons, Comp Cams 268H, Edelbrock carb and Vortec Performer intake, 2200 stall converter
85 C4 Corvette, Medium Gray on Medium Gray leather
Bone stock, as the Good General intended.
Plus an 83 GTI, two Datsun Z's, a Mitsu SUV and a Hyundai. Still working on obtaining a partridge in a pear tree.