I also have the Tri-Y header with a head and cam from http://www.engnbldr.com/.

I made my own Cat-Back from a 24" Flow Master glass pack.
I used 6- 2 1/4 45 degree bends and the noise is just about right. After the exhaust leaves the glass pack it makes 5 turns and that keeps it pretty quite unless I'm really reving it up. Just running around town or poking along a trail it's very quite.

Ralph

1991 Toyota 4x4 Standard Cab Pickup.
engnbldr cam and head.
Doug Thorley Headers
Home Made Cat Backs
30x9.5x15 BF Goodrich All-Terrain M/T KM2