what ever was the outcome on this? Did you convert to a return style system? and if so. what did you change in your tune?

I have heard the hardest part about a returnless system. is the tune.

I am trying to figure out what to do with the fuel system on my 04-08 grand prix.

Does anyone have serious information on the fuel system setup on these? I know they made a change late in 05.. so that would put my 07 in there. im not sure what it was ( from GM ).

thanks