Alwight fellas...
I was looking for ages for info on tuning boxes. I'm a different case cos I have a TDI mk3.
I was basically caught between pointlessly spending big money on a chip re-map and buying some cheap crap off ebay !
So I went halfway house. Basically 2 companies mrhoot.com and hhtuning.co.uk were the contenders for IMO the best value boxes.
The analogue ones are the cheapies, but I went for a cheap digital box for £220 from hhtuning.co.uk.
And F*ck me.... what an improvment !!! I could easily take on a 8v Gti now ! 90Bhp - 110bhp. 25% increase. Fuel consumption is a bit less, but worth it for the extra power. 90+mph uphill !
Not sure how these things work on petrol cars though. I don't think they're as effective.