Keep my '14 350XC-F or '15 Honda 450

So, I turned 30 last year and decided I wanted to start racing again. Hadn't raced in probably 10 years. Used to be a fast B rider in woods/harescambles but couldn't hang fitness wise when I started riding again.. I've been running 30+ B/C this year in Moto and been racing Hare Scrambles. I've done about an equal portion of both. I have a 8 year old little brother (yes my Dad got remarried and had another set of kids) and he's been doing both as well but seems to like moto a lot better. So it's a little easier to jump in the rig with them and go do moto. Tracks are closer, and races are more often, etc.

After getting whooped on in Moto the first half of the season, I got my ass in gear and started training and doing hare scrambles. Dropped about 30lbs and am now about back to where I was when I left off 10 years ago. Did some more moto and it was much easier. So next year, I'm going to try to race as much as I can strictly mx.

So, should I keep my XC-F and convert it over to a SX? I already have the SX tank and suspension setup for MX. I pretty much just need new wheels/tires. I know I can't fix the 5 speed.

OR

Should I get a 450? The 450s seem easier to ride MX with to me. The power seems more usable and spread out where the 350 revs to the sky. Despite it having a little less HP, the 350 to me seems like it is more "hold on for dear life" in certain situations because of how revved out you have to keep it where the 450 I can just roll on the power. That said, I ride the 350 just fine. I have gripes about it Chassis wise though.

I was looking at a '15 Honda 450. I'd incur about ~$3000 extra in debt with the trade-in, ~$2000 if I sell it myself. But could recoup some of that by selling off some of the extras. I have a legit job so the money doesn't bother me too much.