OP - car looks great.
In regards to 1m vs 135i convert. The only parts that carry over from my research, motor and front axel carrier, bonnet, boot and the actual shell. I quoted up all the parts to do the conversion correctly and i was up to around $35k AUD without mechanical labour and paint and panel. That is with all new parts tho( the rear end was about 15k of that price, and 1m spec gear box was about 6k). Im sure USA new prices are significantly cheaper than Australia however.