I've retrieved all my ST200 bits and pieces from the loft and I reckon I'm going to give it all a go this weekend. I've not made any changes to the Cougar in months!
Get an extra pair of hands if you can, mate. There's a weird multi-way vac tube that comes off the underside of the UIM (amongst other places) which is impossible to install after the UIM/TB are in position. Having another person makes a world of difference.
Also, if you're replacing the LIM, put the injectors into the fuel rail
first. Seems counterintuitive, but it's actually easier than putting them into the LIM and trying to push the fuel rail over the top.
Once the injectors are in place and the fuel rail bolted down, but before the UIM is mounted, whack the battery on and turn the key to prime the pump (but not start the car, obviously). With the system thus pressurised, have a look for leaks - I don't recommend a lighter for this - which will tend to pool in the middle of the V. A leak means you pinched an injector seal.
Failure to idle correctly is a sign that you've got an air leak. As Tony will tell you, you must be scrupulously clean on the mating surfaces. Get Stanley blades, rags, and isopropyl alcohol.
Lastly, if you have a set of green injectors, don't bother with them unless you're planning a re-map. And if you
don't have a set of green injectors, go and get some injector seals before you start the disassembly. Um. Trust me on that.
Good luck, and please feel free to call me if you get stuck on anything!