MJF
Well I've done street tuning and bolt on kits before, but I know
horsepower freaks will do it for you at a professional level and tune it on the spot with their dyno. They deal in all range of cars from vipers to evos. I'm sure working on a toyota engine in a Lotus wouldn't be that difficult and probably cheaper then going to Park Place LTD.
Edit: I just checked Horsepower Freaks website and they offer aftermarket Lotus products.