i have had the headers and h-pipe in the past they both fit great.the only complant was that the headers were painted not ceramic coated.the long tubes you have too search for a three bolt flanged h-pipe.they don't make one for the L/T's.
I had headman headers on my S-10. They fit perfectly, but thier black paint finish got really junked up real fast. I'd get them if $$$ is a problem, otherwise I say look somewhere else.
The thing I have noticed about cheaper exaust systems is that after you fix all thier flaws, and sometimes replace them a time or two, you paid more than for a expensive system. Headman, I've heard good and bad things, a few people complain that they have leaks but once they are fixed, they are fine, but don't last as long and end up replacing. After you add up all the hassle and time they cost more, then again, some people swear by them.
I had Hedman's on a truck I used to have. They were excellent. The black paint does go away almost immediately though. If you don't ceramic coat you can have them sandblasted bare and finish with the VHT header paint. That stuff holds up well and has a nice appearance. I've recommended them to several GM guys I know who are also very happy with the fit, etc.
I've had the shorties, almost a year now. Here's my .02:
They were supposed to be direct replacement for stock, but had a 3 bolt flange, so a little extra work was equired to install. And, I have found it impossible to get a spark plug boot to clear the header at the #5 plug without dinging the header. Even with that, I may have to remove the header to change the #5 plug. That may be a common problem with other headers, I don't know, but it seems to me that if you advertise stock replacement, I shouldn't have these little problems. Performance wise, they seem OK. Alot better than stock for sure.