All depends on ur budget really and how much ur willing to do youself, zvh conversions are good but arnt the cheapest then u got ur management to sort etc, the easiest turbo route would be fitting either an mfi turbo engine and loom or going for the efi fiesta turbo engine if u can find one!! Or as said n/a isnt all that bad, my old xr2i engine was rebuilt, ported head, cam chip etc etc and althou was only about 128bhp on the rollers when the cam kicked in at about 4k revs it pulled like a train!! and upset a few people lol.

Have got a cabby with a 1.8zvh engine in out the front but its being stripped for parts now to make room!! It never actually did make it on the road lol.