_steve_

I would also suggest that you search for old posts on this subject as it has been thoroughly covered in the past. Unfortunately you will find that the EFi manifolds are as "rare as rocking horse pooh" and very difficult to find. I know guys who have been looking around the globe for ages but still havent had any luck finding one.
Of course I wouldnt let that stop you, you have the option of making a manifold to suit an aftermarket throttle body or a throttle body of another production model. Then there's the need for an engine management system and the necessary sensors, I use Haltech EMS because they are simple and reasonably straight forward to map etc.
The sensors can come from almost any other car as long as your EMS will recognise the sensor type. This is a big subject so do your searching/homework and good luck.

Paul.