When i bought mines it came with the 5th injector that andy got fitted when he owned it, it uses the cold start injector line of the AFM leaving that disconected.

in all honesty i havnt driven an RST without one so im not the best to advise on the matey but as T28's car shows its not a necessity (very nice by the way you taking it to showcase on the 28th mate? )

Also im popping through to AVA next month for a rollers session to get the car whupping ass (even more )

Pete