As above. As long as they chop ALL the rust out and replace with new pannels then it shouldn't come back again tbh i scraped my last one because there was to much rust and ended up cheeper to buy a clean one But there realy was alot of rust one mine. Both wings, both rear archs, both sills, rust scabs on both doors, few holes on the floor pan and i damaged my rear 1/4 If its only one sill or a wing then get it done but it sounds like your mates was like mine.... not worth repairing