Search Sierra and/or Cosworth on eBay and you'll come up with a lot of stuff from BAT. They are getting rid of most of their old stock I think. BTW, much respect to you fo doing this car, they are awesome and IMO still look great today, especially with some Cossie body parts and lights. A really bitching motor for that would be the 3.4L SHO V8, but obviously the stock 2.3 is easier. Cossie swap is always cool but expensive. And don't let anyone tell you the rear suspension isn't good for drifting, more than a few cars use semi-trailing arms and slide with ease. Nothing can compete with a solid axle for shittiness

If I remember right, the stock T-9 tranny isnt very strong. T-5 swap is easy though and make sure to check www.ebay.co.uk for tons of Sierra and XR4i parts.

-Sean