Sid...I have a similar build as you are planning and while I don't know that my pipe will build the most power, I do feel confident that it's one of the best ones on the market.
I did a ton of reading and researching and asking questions like yours before settling on the D&D Fat Cat before I became convinced that it was the right one. In fact, I think I did 2x the research I normally would because I thought the pipe was a bit ugly but once I got it on the bike, I actually liked the way it looked.
The power difference was noticeable and easily apparent and most dyno charts that you see will back that up as well. The 2 into 1 pipes typically fatten up the 2-4k rpm range on the torque curve and will often match or exceed top end power of many 2 into 2 pipes.
The fat torque curve makes the bike much more enjoyable to ride, i.e. you won't have to downshift as often. You can find more
D&D Fat Cat reviews here.