The reason behind running richer is because the air is colder and denser, more air goes in so more fuel needs to go in.
From what I hear about Irvine is you really don't want to talk them anyhow. I think the only way to solve the Irvine problem is for you guys to find a local shop and have them order parts directly from CEN. It should be possible if you convince them that all of you will get your parts from them and not Irvine.
CEN not responding is somewhat normal. Like Scouser said they are limited in what advice they can give and there are some really knowledgeable people around here that aren't afraid to try new stuff and different manufacturers parts.

Poor Judgement, this wouldn't be a hi-jacking if you made regular updates.
That really is good news about the diffs holding up.
I still haven't broken anything on mine with the buggy shaft mod but I also haven't really abused it yet. I have been to busy prepping the Mammoth ST to really take then CEN out and thrash it.


rolland