I have a CF strut brace which came installed on my
135i.
On close inspection, the strut does indeed appear to be a
very tight fit, just about as close to actual contact with the air box as possible. Admittedly, this is hard to see from the angle of this photo...
Although I had not planned on taking grand leaps through potholes, anxiety over cracking the strut will probably keep me on my toes a bit more. At the risk of stating the obvious, I noted that the CF portion of the strut does not extend fully to both ends; instead, you have metal (presumably aluminum) flat tips at each end where the double bolts clamp the strut into the engine compartment. I cannot attest to whether this improves
- or compromises - the durability of the strut as a whole, but I'm sure it's necessary since CF is so darned easy to shatter
(only a madman would go near it with a bolt!).
For what it's worth, I've driven 135s with and without the brace; for me at least, the stiffness is noticable (inclined S-curves and hard cornering). One admission:
Until last post, I had no idea an all-aluminum version was available! Doh!