well just to make this clear you realize that the SOHC is 2 cams and the DOHC is 4 cams. Also I don't think it will be that easy to go from a SOHC setup to a DOHC setup on the same block.
Well on my friends 98, he has the bassani o/r x with the original 40's and I think it sounds hella good. I'm actually trying to get him to sell me his car.