I like my Sinister kit, I've had it 3 1/2 years no issues.
With Sinister you'll retain the stock look, grid heater, way easier install.
The other kits mentioned you'll be changing everything including removing/buying the up-pipe that's blocked off.
On the link you provided that's a additional $239 on top of the price of the kit, this is something that's really never mentioned until you pull the trigger to buy.
You have to either weld the opening closed or buy another up pipe, no matter which way you'll have more labor involved.
If I was building a racer, then I might go that way, but I didn't.
If you decide on Sinister DO NOT BUY the knock off copy cats for less $$$.
Stick with the real thing.
When Sinister first came out they had problems with the stock up-pipe block off plate.
They re-designed this several years ago, before I bought mine.