I never had a lupo, but a simlar car a 1000cc fiat uno and 1.2 panda. The up is much better than both although I did enjoy our mark 2 panda.
The engine is great. Make sure you run it in gently and after 1500 miles it starts to loosen up and then you can enjoy revving the thing and enjoying the strange, but chirpy noise.
I used the same run in technique with the Uno and it did 205,000 miles with no engine problems.