Looks a great looking unmolested car to me. The fitment of a strut brace is hardly a serious modification, I have a E-Tech strut brace (they can be unbolted in 5 mins) fitted to my car, which I would describe as a totally unmodified car. By saying the car is totally unmodified most people take it to mean, no trick suspension, chip mods, BBK, intake/exhaust system mods, hard bush kits etc. The CSL wheels and the strut brace enhance what is a VERY nice car and I'd have no qualms about purchasing a car of this quality if I was in the market for such a car. I honestly would not be put off by one word in the description. I think you would be hard pushed to fine a better Z4 MC, you might find one cheaper but condition would not be as good.
The C-TEK battery charger is quite evident in the engine bay and is not a race chip attachment.
However as is normal you have to go to LOOK at a car to get the full story and see what it is like in the flesh and ask a few questions if you have any doubts.
Just my thoughts on the car.
GLWTS , we've got it up on Z3 M Coupe Forum website in the for sale section as we have some Z4 MC owners on the site.