all i need is good mufflers.

I second cu440da's recommendation!

For a Slant 6 I recommend a Spintech muffler such as the following:

Pro Street 6221 (2 1/4")
Pro Street 6331 (2 1/2")

I had the 6331 on a Ranger V6 and it sounded great, although it did drone a bit at 2,500 RPM in 5th gear on the freeway. I also had it dumped right after the muffler.

The great thing about the Spintech Pro Street muffler is that it's very compact and not overly loud, but people did always tell me that they heard me coming.