Matt I know it's not an easy decision to make and you're not in the best situation financially just now but it'll come good in the end I'm sure.
Personally if it was me I'd take this opportunity (if you really love the Zed) to make it a V8 or forged engine or FI especially if you plan to keep the car long term (eg 5-8 years + at least).
To afford my supercharger mate you have no idea how much stuff I sold & how much I saved. Haven't eaten out, been on holiday or anything in years, ..gave up smoking cigarettes and other small joys like buying magazines etc when I wanted.
Went round my bedroom/garage & sold; old toys, airguns galore, Dremel accessories, old car parts, lighters, ashtrays, magic tricks (bought in the USA when I was 14/15), jewellery, r/c cars, r/c car parts, model kits, PS3 games, unused car bulbs/LED's etc etc think you get the idea.
Sold so much stuff on eBay that my account actually got suspended at one point as I breached some sort of income limit.
I'm sure if you can start doing something like that it will help your finances as it's amazing how much stuff we accumulate that really just sits there doing nothing.
Good luck and if I can help at all I will ~ I'll get a Lotto ticket for Friday so you never know.