I have the same ideas about the 1.8 zetec, but it amazes me how little information and experience there is within the Morgan community compared to the Westfield/Caterham etc owners where such tuning is the norm. Perhaps Morganeers are inherently more conservative. Personally I think the trads need a little more than 115 or 145 bhp - but not the 230+ from the v6 which is excessive IMO (let alone 3.9 or 4.6 v8 motors!)
I will probably have a local motorsport engineer deal with my zetec, as then I can get support locally. It won't be cheap - throttle bodies, inlet/exhaust manifolds, and custom ECU will be about £3k.
Nigel