I am the guy cash is talking about...
Best place to put them is right in the bend coming back after the cats. It gives the loudest sound. The further back, the less sound.
The install is simple but yes, they need welded. It wouldnt make a rats ass difference what exhaust you have, they all should have this bend.
The main thing, make sure you test fit and lay them out FIRST, before you drop the exhasut. There is NOT a ton of room up there and you dont want them to hit the floor pan or hang down. Hold them up there and mark them.
This is where cash's will go too. The only set I installed that are in a different location are on a friends car in PA as there was a clearance issue. We put them in the back near the muffler. His car is not quite as loud as mine.
If you need any more info, let me kwow.