I was wondering if I need these. I don't track my car.
I actually dont drive it hard. My concern is after it is out
of warrenty, is there a design defect that the strut bushings
will mushroom out, causing me an expensive repair.

I'm planning to get the garmin mount anyway, and I would
save on shipping. But, I don't want to throw money away
either.

I just started a long commute and I'm counting on this thing
right now. Eventually I'll have my honda servicable again and
it wont be as critical. But also, if I can avert some thing that
should not be in the first place (I have 270k miles on my honda
bushings still going strong) I'd spend the 150.

I'm just trying to figure out if exploding strut bushings are
a real issue I guess.

 

Mushrooming does not seem to be much of a problem for R56. I think you could save your money, especially given your driving profile.

 

In my opinion, it looks like the STD's made from VIP custom parts (http://vipcustomparts.com/minicooperparts.htm) are a better product than the CravenSpeed one's, and they're a couple of bucks cheaper too. Also, if you're just worried about shipping, VIP's shipping is free.