The 135 opti is gonna be hard to sell, it's basically a pontoon pusher so you'll be practically giving it away on a straight power upgrade. If it's all about money then yeah you'll come out better selling it and then buying a new(er) rig.
I wouldn't advise anyone to buy a NEW boat, cuz there are way too many good used ones out there.....but if you have the coin and don't forsee any money shortages in your future they why not, you only live once.