Leaving out the sound factor, which will give you the best results on hp and torque. A friend has D&D 2 into 1 on a stage 1 and gets 100 torgue on his 103. I'm guessing 2 into 1 is best?

 

D & D Fatcat.

 

Yep...2-1...

 

Totally agree, 2 into 1 is the absolute best for HP. I don't have one, but I hear D&D Fat Cat is great.

 

Dragula 2-1.It out performs the D&D and it costs $400 less.

 

looks like they sell a Fatcat and a Boss fatcat. Any opinions on either. Read somewhere that the Boss Fatcat is for 09 or newer but also read that the boss Fatcat is for big hp motors