Its been a while.......

I have tried searching on other boards and yet I trust the response from here the most. When I had the money back in the summer I was looking to get a set of PI heads for my Romeo Grand Marquis. All I knew was that all 4.6 heads in the PI range would work. JY would not sell me some without specifying which ones I needed. So now I pose this question to you all..... which heads are better for the PI swap on a Romeo engine? Would it be the Windsor heads or the Romeo heads? I guess what I'm wanting to know.. which has more potential for power further down the road?

Thanks,
Nate