since i ran it this year I can give you actual facts instead of speculation
1) in mexico they have their own classes, just like we do, and in 2003 they ran as part of the rally just not counting for the 'international'
they have basically PGT ('MN4' "Mexican N4" and 'MA8' ("Mexican A8 / Open")) all the way down to the little 2wd classes
the mexican classes are very similar to canadian PGT and Open rules, in that anthing goes but you run 32mm and 34mm restrictors on the turbos
basically 'field filler' - a rally can apply for dispensation to *any* of the rules for WRC events if it is in the best interest of the event, and they are usually allowed. I am sure that there will not be so much a need for field filler this year (2004), but if it had to be done it would not be a problem
2) some entrants that were N4 entered but deemed to be N4 illegal were bumped into MN4 - this happened with more than one car
3) this year the one of the FIA scrutineers present (Jerome Toquet) is the same guy that scrutineered my car 3 weeks prior in Sweden, same guy that checked it in New Zealand, and also same guy that checked it onwards in the Grp N championship. Although I am not sure if he was listed in the sugg regs as a scrutineer of the event, he was there to help the actual scrutineers
4) some cars that had borderline N4 legal PRIOR to the event were told that they had to make changes, or else they would more than likely fail post-event scrutineering/tear-down, should there be one for their car. Some of these were very small like not having laminated safety glass. But the process was correct, i.e. "scrutineer to team, I am just telling you how I will rule if you are in post-event teardown", and from the cars that i saw this happen to all made changes prior to the event starting. Nobody seemed to mind me eavesdropping but then again i speak French... and I dont think anyone got that
5) the winning cars that were impounded, as per the supp regs, were actually checked, like at many other events (non WRC events) around the world (and even non FIA events, just not in USA), and the winner was excluded
6) you guys who are slamming FIA stuff are maybe slamming SCCA stuff put forth 'in the name of FIA' when it really isn't so, but whatever
7) if you want to do a WRC, do this one because most of the others are oversubscribed, this one is close to home, and this one will probably be easy to get an entry into it and also you can rent a Grp N car from Vermont, AV, Cascade, **or** a lot of the WRC teams that will be there will probably do a 'rent and sell' deal etc. that you already know will be legal (put in in your contract). you will never be able to do it this cheaply
8) Funding permitted, I would like to be there specifically because of reasons 1-7
9) I agree that of the cars i have seen recently in ProRally in Grp N I am not sure any would survive a post-event teardown run according to proper FIA standards. But competitors please dont be offended by my comments. Even the guys in the WRC events fail tear-downs. Since the rules of SCCA ProRally deem that it is up to competitors to police their own classes (even though this apparently is not always happening) we will never have standards up to snuff - it is not the competitors fault but the way that we handle legalities (even though we do have some isolated cases of pre-event scrutineering and classification, it is not in the rules).