You can get a new carb setup for under £300 these days - I will phone up and see how much it actually is tomorrow, but I'm sure its around that if not alot less, I can get discount too so its even better (bennefits of building kit cars lol and knowing companies VERY well lol).
But with carb setup, you can download megajolt software onto your laptop, go out for a drive, plug it in, bring up drive you went out on, then either custom map it, or let the program do it itself, then drive it again, and repeat until its perfect. Normally it takes 1 or 2 drives to get it spot on - used to do it all the time with the kit cars. You can even do it while driving along, but its easier to do it when you get home.
So yeah. Thats something about carbs.
Bodies, well they are fairly straight forward, use most of the original sensors and can also be tuned on the laptop same was as above with megasquirt software.
Power outputs of both different setups will be quite different, the advantage of having TB's, is its more eco friendly. I think on zetecs carbs are better off, I will phone Graham and talk to him tomorrow about it, as I wanted to do this with my car soon anyway, and I'll get him to do me a deal

lol