Ok so I've just bought a chameleon suit for my starting character, and I want to give it some thermal damping, and under cost it says Rating x 500Y, but it doesn't have any cap for rating in the table or in the description. I did an errata trawl and couldn't find anything. Has anyone else noticed this? Any suggestions?

There's details about armor 'capacity' in Arsenal, but I can't get to it right now.

rating for mods is 1 to 6. 1st paragraph on page 317 in the main book. and from arsenal, armor can be modified for 6 or higher armorx1.5 points of modification, so chameleon suit can get 9 points of modification total (6 thermal and 3 something else).

Cap of Sum of all Ratings: Highest armor value (Bal or Imp) x1.5

Provided that you choose to use those rules since they are optional.

Sure, but it prevents someone from building my old "Mage Coat" and laughing at all of the elemental effects, I'm not sure which of the rules I'll end up using yet, but you can bet that I'll be using one of the rules to limit armor mods.

It's annoying that Arsenal nerfed armor mods, but it's also a good thing. It's just stupid to have one piece of armor with every mod at 6. It messes with game balance if everyone has every mod. Nobody will be hurt by tasers, elemental spells, thermovision will be worthless, contact vector chemical attacks will be a joke... The only way a GM will have to really put the hurt on players will be to blast holes in them, which can get boring.

And Arsenal also provides lots of new stacking armor pieces, so it becomes feasible to wear more than one piece. So you can no longer put the kitchen sink into a suit of 100 armored clothing, but you could reasonably wear a form fitting full body suit with 9 points of mods and an armored vest on top with another 9 points.