I've got a Boris X9 with about 1,200-1,500 miles on it and I've been thinking about throwing a BBSHD on it but Luna will come out to about $1,350-1,450. I can buy a Purpose built bike for only about a $1,000 more. This is not my primary bike but my father is disabled and I want to get him back on two wheels because he misses cycling. Is my old fat bike worth doing the conversion on or should I just get an already finished bike?