Does it even have variable cams ? 1997 is quite old for that sort of thing.

Depends how fancy you want it, but it should be easy to find an ecu to run it as a basic V8, group fire injection for well under £1k.

If it has COP with built in ignitors, even easier as you can do it with only 4 ign outputs.

Although if it has conventional coils, you can still do it using external amps to drive the coils via 4 ecu outputs.

VEMS and MS would all be at the cheaper end and are both "DIY" originated, although there will be plenty more than that, and both have come a long way from their original designs.
I see a guy mention recently that the VEMS has some serious spec now for the price
http://shop.vems.hu/catalog/assemble...ller-p-48.html

Adaptronic do a budget ecu that's around £600 and has a decent spec

http://www.efi-parts.co.uk/index.php?productID=248

But really there are dozens of options without spending mega bucks.

Link, Vipec, DTA, Haltech, AEM are a few that offer "cheaper" units too.