looking to build first kit car

[amg86]

First of all I'm pretty much sorted on the front of space to build tools and know how and the many years of my dad's mechanical sense I'm ok with building it. Right to the business part I'm pretty much set on a Westfield mx5 conversion kit car.
1. Can u use the 1.8 engine
I'm open to other kit cars I'm looking at a budget of around £10000-11000.

Also the one thing I'm not 100% on is the wiring loom how hard or difficult is this obviously u label and take photos or does it come explained in the manual