Headers VS Manifolds

OK....here is the background... My 66 started life as a /6 car....because of its survive-ability( pretty much zero rust) it was deemed to become something greater. So Off I went to find a 340 block...found one...looked for x heads...found big port U heads...I am OK so far....cleaned it all up did the heads did the block and ran it through an assembly process....ALL GOOD....( so far) Found a failing 727 snatched it and started to pump it up...went from 3 to 4 clutch drum & clutches, 3 to 4 planetary s...ohh rah ....starting to come together.... found a 8 3/4 sure grip with a 355 cleaned it up and re-set everything...its tight and solid. found 3 v8 k frames, 2 were junk and the 3rd seemed to vaporize along with its owner ( I think he left Michigan.) Gave up on that and went with shumaker conversion mounts and stiffer torsion bars...there isnt that much difference in weight so...off we go.... OK now so the set up is /6 k frame, schumaker conversion mounts and a 727......had to modify the trans mount the stock one is about 2 inches too tall and the 727 hits the tunnel...drop it down 2 inches and off ya go...... I talked with TTi and they understand the config and say their headers will work.....IF I modify the trans cross member, the brake lines and block and use an expensive mini starter which assumes I have a regular torq converter ( which I do not running 2800 stall)..... SO the TTi's cost around $900 and then there is the $200 starter and a flurry of R&R to install not to mention it will ALL fit like skin ( meaning WAY TIGHT) in pretty much every aspect....... so here is the questions

1. Is the "performance" (and I mean REAL performance,) obtained from headers going to be worth the $1200 cost?.....

(I am not in bracket racing or any other kind of racing.....I want to burn out here & there....and nail it on occasion.....quite frankly I did not spend all this time building this thing up and restoring it only to beat the hell out of it.)

2. SURE I like to go fast but am I REALLY going to notice 10 to 20 horses? not at the clock/strip...but the pull felt behind the wheel??

3. so does anyone have a setup like this?
( OH I have the stock 273 v8 exhaust manifolds and cant seem to find if there is a difference between the 2bbl v8 manifolds and the commando v8 manifolds???? but I have to believe they are as big as the 318 ( never saw any 318 manifolds to compare))

I am leaning toward the manifolds for a couple of reasons....
1. COST
2. COST
3. Hassle ( modifications, installation & maint like oil changes etc)

so WHAT say you? and please provide some background and reasons for your statements....I am interested in your thought behind your comments
thanks
66cuda

headers? or manifolds?