Depends on a lot of things buddy, I realise you're hungry for information at the moment,... but there's a lot of threads about costs and work involved already, It would be worth your while spending some time Researching this yourself so that you get an idea of what's involved rather than relying on other peoples information too much, take a look on here and you'll see that no two Alternative engine conversions appear the same. Get onto the 16V Mini club, go to the TMF 'non mini engine section', put the kettle on and have a long read with a notepad infront of you. This is what the forum is for, it is an enormous Archive for people to use, Yes it is constantly being added to, but there is so so so much already here that has had so much time put into it, it's a shame not to have a good search around first
Overall, If you're willing/able to do the bulk of the work yourself you will save a lot of money and you will know the car like the back of your hand. You will need to be able to weld and fabricate VERY well if you want to create a car that isn't a deathtrap,... A good solid knoweledge of how electronics work is a plus. You need to consider insurance costs once the conversion is done - as it's very likely that the insurance could easily cost more than the conversion depending on your circumstances and age.
Don't take this the wrong way buddy, I want to help you as much as anyone else, but looking at all your current engine building fiascos

(hats off to you for going in the deep end) and reading through the other threads you've been creating recently I have a good recommendation....
Get your mini fixed properly and safely, Don't rush this, Drive it, Enjoy it, Take good care of it, Be methodical and precise with your repairs. The knoweledge and experience of actually running a classic car through a year will put you in good footsteps. Please don't read this as me attempting to be all 'wise monkey' on you. But first it was broken engine built poorly, then it was want a turbo, now it's engine conversions, Just fix the thing and drive it, then decide if you really want a mini or just buy a cheapy hot hatch that'll probably perform better for less money.
Edited by Retro_10s, 27 June 2011 - 10:26 PM.