14/37 is exactly what I plan on running. I currently have 14/38 and it is pretty good, except when im holeshotting, I feel that my 2nd gear is a little to short (I have to shift to third too fast) so I think the 37 will fix that. But Ive got the power to pull it so im not worried about that. As for the carb Ive heard countless times that the 38 PWK 'AS' is the way to go. If I feel i lost some bottom with this there is always a reed spacer. You said you taper bored your 36 PJ, but mine is a PWK 36 and im not sure if you can do it to this model.

 

I am not sure about the PWK series being able to be taper bored, probably will have to ask a performance shop about that. I dont think you can go wrong with the 38 A/S carb, I just assumed you had a 36PJ and taper boring costs about $50 where the 38 A/S cost around $200 for about the same performance gain.

I run a reed spacer, though I dont know if it hurts or helps. When I put it on I couldnt tell much difference. Ask 10 people, 5 say it helps, 5 say it hurts. Verdict is still out on the reed spacer for me.

Good luck with the setup.

 

The tag on the pipe says TRX Race. There isn't any evidence of tinkering with it's tuned length.
Maybe I'll try to take a photo of it and post it somewhere so we could compare to see if it were labeled incorrectly.