exide megacycle agm 200

That seems a bit high.  I think Advance Auto quoted me $420 after Colorado's ridiculously extortionist 8.5% sales tax - for a pair of Yellows a few months ago - I used to live on the East Coast and Batteries Plus is seriously overpriced.  They're good for obsure watch batteries or maybe for a Carbon Monoxide dector, but you should shop for car batteries at auto parts stores, seriously dude.  Or even three seconds on google:

http://www.autobarn.net/opbatdeepcyc.html

Free shipping and no sales tax.  I'd be real suprised if you couldn't fit that in your car - the difference between that battery and the exact size you are looking for is like 3/4 of a inch.  Battery bays are pretty forgiving.

I find this all highly suspect, particularly given that you happened to walk in right before the price was about to double. (?!)  Absolutely none of those Exide links give a amperage at the alleged 200 minutes of reserve capacity, so this number is totally worthless.  To be honest, the battery looks like a standard deep cycle - but for a RV?  I dunno - again there really isn't enough information to go on.  I can tell you that I wouldn't install lead-acid batteries anywhere near my stereo equipment - the Yellow Top's a dry cell - I would be MUCH more comfortable with spill-proof Optima's in my trunk than a sloshing acid battery.

I've been using Yellow Tops for awhile - these batteries are incredible - and I'd be extreamly suprised if ANYTHING of the same size could outdo the capacity of a Yellow Top by "alot."

I mean return them for no other reason that you could get equivalent gear for less money - or better gear for the same amount.  I couldn't imagine those Exide batteries would outperform a standard DieHard deep cycle. 

Again, the d34 is a like 3/4 of an inch wider than the 31 - I installed a d34 in my 31 battery bay - this is a physical size thing, it doesn't make a difference electrically.  I'm sure you could get it in your battery bay, but the point really was that Yellow Tops do NOT cost 280 dollars anywhere except Batteries Plus.

Kinetiks are pretty popular amongst tuners these days, and from my understanding is comparable to the Optimas - outstanding for car audio installs - if a bit more expensive.  I don't really care for the stylings of the Kinetiks either - but that's not really a big thing.

The 31's are a little taller and thinner - they have slightly different specifications as far as total capacity, CCA's, etc., but the point is that they are Yellow Tops that are built to take abusive current demands - and this is really the key here - not total power storage capacity but the ability take the abusive nature of a large, subwoofer amplifier.  Constant 100-amp spikes are much harder on an electrical system than, say, a steady 20-amp pull.

I mean - I'm sure the battery you got will do the job - you certainly paid enough for it and you are paralleling TWO of them.  All I'm saying is that for my money, I'd get Optima's.  Or Kinetiks - but not lead acid Exide batteries.  Here I do think specialty equipment is warranted and appropriate.  Reds or Yellows (well, Yellows) - but not Lead Acid fishing-trawler batteries.  I just don't think that is an appropriate solution.  Perhaps some members here would argue with me - I dunno.

It may not make a technical difference in your particular installation, but IMO a proper car audio battery (or two) is the *proper* way to do things.  Sort of like why you are fusing all over the place. 

ESPECIALLY when you are paying the same amount of money!