Exhaust for 66 GT K-code... having some problems

My dad and I have just about finished our 18yr father/son project and am down to the exhaust... We need a hi-flow exhaust to handle the 289 having been bored 60+, 14.0:1 Jack Roush Pistons, running ported and polished 351W heads topped with BlackJack 3" dumps. Our dilema lies in that weve decided we want to retain the stock exhaust exit points in the rear valance AND use the stock trumpets. Wed prefer 2 1/2 and are willing to cut the trumpets to fit. Has anyone tried this or has any clue who could produce this system for us?
Im sure judging from a few engine specs y'all can see that a good exhaust is key. We've gone all-out with the engine, and trans, and just need a great exhausto get it tonned down a few decibels. Yea, the roller cam, roller rockers, twisted crank, Roush pistons, Eddie RPM II intake, and 351W heads, sound great but the sound police have cracked down on us from running open headers and so has DMV. ANy input,questions, advice, or any other form of inspiration would be great so that we can put some miles onthis car and enjoy almost 20yrs inthe making... Thanks guy/gals!

Brandon
Firefighter/EMT
New Kent, VA

Well it is a unique car...and a very fast one at that... And I just dont want to loose that crisp cam that it has... that sweet "plunkita plunk plunk plunkita" of that high lift cam is what i dont want to muffle. Classic Musclecar is what we're going for...and I told dad that i was going to look at H pipes over the X. Thanks for the sites, im going to check em out before I settle down and slap the greenbacks on the counter.
Im guessing you have Flowmaster 40's on yours? Im lookin at flowmaster and want a Single Chamber. Does it matter where I put them in the system (closer to the headers or farther back)?

I think we'll just end up putting single chamber Flowmasters with an off-road H- pipe. The sound clips seemed to be close to what I was looking for even though none of the cars had a cam. BTW, nice GT350 look-alike. Hopefully ours will get a Shelby grill and front air dam eventually.