i'll get right to it, going with the jet hot LTs:

A.) Is coating the y-pipe important?

B.) For clearance, is 2.5" y-pipe the way to go?

C.) Should I get O2 sims despite the fact that I am going dual cat (have to)?

 

1. IMO no
2. the collector should be the lowest point of the header/ypipe. the y pipe should not effect ground clearance, 3" is standard for long tube y pipes
3. you will either need
rear o2 sims
or put additional o2 bungs for your rear o2's to work properly.

how strict are you emissions?

 

I went with 2.5 inch duels. I think 3" is too big unless you are making 700+ hp. Since you are in Austin, I wouldn't coat the y-pipe. Low salt and pretty dry area. I think that Lingenfelter dude made more power with 2.5 pipes than 3 inches on his cars. Thier was a post about that here some time ago.

Jeff D.

 

he is talking the size of the y pipe not true duals.
3" is not too big for the y pipe on longtubes

jesse