Tiforce, sumo or not

[BanditKing]

I've got an opportunity to get a Tiforce hi-mount 4-2-1 full system in either sumo or non-sumo.

is there a real difference between the two? I'm not planning on doing any forced induction, so is there any point getting a sumo?
won't the larger pipe drop my mid-range HP?

But i heard that TiForce is dropping the non-sumo line. Any ideas why?

Thanks for any advice.

BK