I am looking for an S-300 varient to replace the hx35 in my twins and saw that the BD super B is a modified s-300, the htb2 from high tech turbo is a modified s-300 and J.R. Adkins is supposed to have one out, but out of these 3 which one spools the quickest and which one cools better

 

It probably comes down to who has the best price and which one can be installed easiest.
With similar sized wheels and housings your going to see ABOUT the same performance.