a more modern/compact (and expensive) option is something like an moto gadget m unit v2 - designed for motorbikes, but very useful on cars with fewer electrical circuits..
motogadget m-unit
..I have one in my track car and its a super-simple and reliable way of sorting out all the non-critical wiring and things, and compared to something like a motec power controller its very very good value! especially with the m-button to neaten all the switch wires up
