I was VERY happy with the 1.5 when I was running it.
You won't notice a big difference until you turn the boost up a little. Are you still running stock boost? Get a hold of a wideband and see if you can turn the boost up a little.
I was running 10psi on a BNR hybrid with the V1.5, Greddy FMIC and 720's and made 294 horsepower.
So how are the 720's working out for ya?