when i had mine i looked at the puma lump as well, but if i had one now i'd look at at motorbike carbs, work like throttle bodys. im sure you can get a full set up for aroung £650. now that would be good. all very well saying put a puma lump in but in standard for your only gonna get a 30 BHP increase on a std zS lump. and it costs more than a grand to do the conversion and then cash to tune it.
tell your mate to get on somewhere like
www.zsoc.co.uk or.com i cant remeber but they will have alsorts of ways as theres a versitle group of peeps on their with different ideas.
i wonder what a rsTurbo'ed Zetec s would go like.............