I have had a mate of mine stroke his l20 out to a 2.4l with extractors webbers, the thing was nuts, lots and lots or touque, rev range was still good, these motors are just about unbreakable, keep the oil and water up to them if they leak and they will go for ever.
I also had my dat 1600 with an l20 twin webbers and exaust they go really well, but one down fall of webbers is that you have to tune the prick all the time.