The 6466 should 60' and 330' better then the 45a on your setup and put you into the 9s,For me I am looking for a super fast spooling turbo and from what I been told it does. Also I don’t see the point of putting a 8 sec turbo on a high 9 second car. Price to me is the only draw back on the 6466. I believe the reason why Jack Cotton recommended the 6766 is cause you can’t get a turbonetics exhaust housing for the 6465 or they stop making the 6465 can’t remember which it was.
you can get a t-netics housing for the 65 turbine not the 68 from what i remember. maybe its changed now since T-netics and precision are under the same umbrella.