Stock gaskets are the best ones, I am going to re-use stockers because I'm cheap (many have done this w/o leaks, so fingers crossed). You can also pick up a new set at the dealership. The ones that come with the headers are usually pretty lame.

 

Stock gaskets can be re-used many times!
The ones that come w/ the Pacesetters are crap.
As far as connecting them to y-pipe...I used v-band clamps and flanges.
I have been fighting leaks ever since from the welds not holding due to the really thin collector material.
Yesterday I had it changed to a slip over connection using the band clamps similar to the ones pictured in the second post. There's still slight leaks using them, so I may go back and try the copper rtv there.
I still have a pesky leak on the driver's side however that I believe is a crack at a weld where the primaries come together and join at the collector. If so, I'm thinking it will be a PITA to fix due to the coating on the headers.
Second guessing myself now about not spending more on the headers to begin with.

 

That sucks, sorry to hear that. I am crossing my fingers that when I put my LPP's on, everything is snug, tight and fits correctly.

 

You can use the Pacesetter Y and the Clamps listed above or instead of those clamps take it to an exhaust shop and have them weld on some ball/socket joints on the header and y pipe. This is the least likely method to leak.

 

I used the band type clamp from NAPA and the Copper rtv sealant. Also got a set of copper gaskets from NAPA and Stage 8 Locking Fasteners. I have never had a leak any were on my LPP's and Y. Take the time and do it rite the first time and you will never have to F with it again.