Very nice indeed! My brother has an M135i and it is a weapon. It has a stage 1 map with intercooler and exhaust and drop in filters. I think its tunning about 380-400Bhp its bloody quick.
As long as the repairs have been done to a high standard and if needed the relevant dvsa check has been done then go for it if you like it. As above might be harder to move on later but if you get it for the right price then why not eh??