Norris motorsport are the people to speak to if you want to stick with the 1.6, they can get some insane figures out of it. Im not sure on thier prices though as im down south and use power engineering. With a budget of 3K you could quite happily do a zvh conversion but to do a full blown zetec turbo you would struggle. The zvh's are quite common so you could easily pick a good one up for under or around 1K depending on the build etc or you could probably build one if you wanted to with your budget. You can get some impressive figures from the zvh but some people say they do have thier downfalls. This is based on if you do the majority of the work yourself. If you get a garage to do it all i think it will be very expensive. It also depends on what you want the car for also?