Is it worth buying a brand new sub frame for an R series BMW (specifically an r65) or cutting up and welding the original to fit a brat or cafe seat?

The new sub frame will cost me $200 + shipping via /r/CafeRacers https://www.reddit.com/r/CafeRacers/comments/8j3b3h/is_it_worth_buying_a_brand_new_sub_frame_for_an_r/?utm_source=ifttt