The k-member isn't all that bad to replace and steeda just introduced one (they are based 12 miles from here and I know the sales manager so I get news quick) that is very well built and it will work with the stock control arms, that might be something to look into, but if cost is key you may have to fab something. Forst thing I would do is go to a shop and mock up the manifolds to stock heads and take some measurements... see if they fit and latch the ports, etc. Then see where it leaves the opening, top and bottom, both sides, in relation to the last bolt (angle and distance from there) then take a good look under the hood and see if it might work. You're wanting to go into uncharted waters so to speak, so you'll have to be thorough, but often with thingsa like that attention to detail and some inginuity goes a long way, that's how things evolve. Its a lot of work to do something nobody has done before, and it usually involves failures, but for example, back in 1991 I knew a guy who did a twin turbo fox with a 351. Everyone said it was impossible, and nobody had even heard of one, but he did it, and it worked awesome, that thing hauled. The only problem I really see is headers made for the setup are easy to find and not that pricey, but if you take your time you may find it works. I'm going to be at a friends shop this weekend, he's a jedi master with f/i mustangs, I'll ask him, and see if I can mock up the manifolds. I haven't looked into turbo for the stangs much, I want to do a supercharger, but I do know one thing for certain... There is nothing in the world that is actually impossible.
The artist formerly known as SteedaMatt.