I've searched and didn't find my answer. Is the .2 mm increase of the 92 that big of a deal? Or are there changes in the runners also?

I have a mild cam TR224 , with possible heads in the future. I found a 90 with tb for a reasonable price. Or should I just get a 92?

 

the 92 is what i would buy i saw a ported one sell for 600 this week and there is one for 700 ported by vengence
IMO used prices
fast 90mm 550-650
fast 92mm 600-650
fast 102mm 750-800

 

There's basically no difference in power between the two. 2mm opening isn't going to gain you anything and I'm about 99% sure the runners are the same. The 92 just has a few minor upgrades that make it not seem as cheap as the 90 IMO. I would get whichever one you can find the best deal on.

 

FAST 92 ~ FAST 90. They both flow and perform the same.