Nice to hear the progress of the car. Apart from anything, the weight savings should be nice for some extra performance. As above though, your link to the pictures seems to be broken or incomplete. It'd be interesting to see what you've done to the car visually.
I'm all the more interested in this thread at the moment as I recently test-drove a 1999 SEAT Cordoba 1.9 TDi with 90bhp. It was a really nice car to drive, loads of shove from the engine, fairly quiet once you were moving (noisy as hell when you start it up!) and felt very solid. The EU average fuel consumption for the car is 57mpg, which is 47mpg US and around 5 litres/100km. Very impressive as standard so I'm not surprised you're achieving close to 3l/100km at the moment. Yours is probably a little more aerodynamic than the saloon I drove:
