Riley had a xc race Sun. & the 90x did pretty good. There were only 4 quads in his class & he got 3rd. There were 2 beefed up trx 90's & 1 extreme 90. The other boys have been racing a few years & were all 12yrs old so I thought a solid 3rd was pretty good
When you say beefed up trx90's. Are you refering to big bore kits or did they have the same mod's as your DS90X? Are you running stock tires and suspension?
I'm not real sure. The ds90x is'nt a long ways off from them. I still need to change spockets & I think that a larger intake would help alot. My son needs alot more seat time to keep up with those boys, they were both pretty good.