Well, the Italian/Mexican place I go to (I know, strange combo) doesn't really offer the proper rural Italian quisine, since they don't make their own pasta and sauces every night for the following day and I don't think any place outside rural Italy does. I'd say it's the same for mexican, but if you're referring to some of the bigger restaurants that can't afford to, I'd say that around here it's pretty much the same, at least I didn't see a difference between the pasta I had in Rome and locally. The Mexican on the other hand is very different, but I haven't had any straight from Mehiko to tell the difference.