Please take some advice from someone who's been there and done it. Dont. just dont.

Buy a running example without tax or mot, and transfer everything from a running example. the car will cost you around £1000- £1200 for a shitbox but you'll make a little bit of money off selling some parts you dont need.

but if you do it your way trust me you'll spend double buying small stupid bits you never even knew you needed, and even then they're untested. theres no cheap way to get proper (reliable) power mate, it simply can't be done.

if you want to do it for £400, go 2 litre zetec, 130bhp and as reliable as you'll ever get.