How does your buddy even find parts that cheap? I tried to just swap my own chainring last year and ended up with the wrong bolt pattern... twice. That $450 number from @roberts.aaron makes my attempt at home mechanic work look even more expensive. I probably spent that much on random tools and wrong-sized parts for way smaller jobs. His friend must have some serious skills and a magic touch for finding deals.

Sometimes the wrong way just works for the job at hand.

Honestly, it's about the texture too.