Audio Research vs. Aragon

I'm in the market to add a serious 2 channel amp in addition to an existing 5 ch. Adcom, as my new house has a large great room approx. 20'x 30' with 10' ceilings. I'll be driving a pair of B&W DM-640i's backed up by a 12" Paradigm PS-1200 powered sub, controlled by an Acurus ACT-3 pre-pro, and connected with Audio Stream cables and interconnects. I'm mainly an audiophile (jazz), but enjoy home theater every now and then. I was very close to buying the Aragon 8008BB (200 w/ch) for $2,400 when a recent visit to my local high end dealer uncovered a totally reconditioned and re-tubed Audio Research D-115 (130 w/ch?) for $1,500. I auditioned it on a pair of B&W CDM 7NT's. It sounds great, but I'm concerned about the excessive heat that tubes produce as it will probably go inside of an open back entertainment unit. Which way should I go? Any advice would be much appreciated.
It seems the issue is one of sound quality vs. convenience (the ability to hide the amp in a rack). If you're serious about sound quality, then obviously the ARC.
Keeping the tubed amp in an enclosed area probably is not good for longevity of the tubes or the rest of the amp, although if it has a fan (some ARC models of that time had fans) that may help solve some of the problem. Just make sure you have decent clearance above the amp in the rack and have a reasonable amount of room behind the unit as well. It wouldn't hurt to call ARC about this question--they can be quite helpful. Both amps you mention are good ones; I'd go with the tubes principally because I'm something of a tubehead. The other caveat I'd give is that you are using a solid state preamp, and as a general rule it's better to use a solid state amp with a solid state pre, rather than a tubed amp--something to do with output/input impedance issues, maybe, but something I've noticed as well in listening tests. If you feel comfortable about the ventilation issue, you should ask the dealer if you could borrow the ARC just to make sure there are no noticable compatibility issues with the preamp (or try it in the store with your preamp or a similar solid state unit).
I use an ARC VT-100 in my entertainment center. The VT-100 has an internal fan, 8x6550C Power tubes and 8x6922 small signal tubes... I added 2 muffin fans suspended by fishing line, one blowing in at the bottom of the amp, and another blowing out at the top. I made a custom shelf with the center cut out to improve air flow, set the shelf above where the lower fan is blowing, and I think the amp runs cooler than sitting on a shelf in open air.
My brother, I too have been down the Aragon/Audio Research path. I had an 8008 driving my 'pans. Then put in an ARC Classic 60 and passed through the pearly gates of hifi and into the heavens of sound.

I'd go with the ARC D115. Heat in an entertainment center from tubes would definately shorten tube life. Obviously you should place it as high as possible relative to the other components in there.

Since you have an open back, it shouldn't be too bad. I'm not sure if the D115 has internal fans like most of the other ARC tube gear I've seen. If it does then you should be okay. However you could do the external fan routine as mentioned by J_K above (although I'm not sure what "muffin" fans are).

My amp is in an closed entertainment armoire. I bought a couple of little 3" or 4" black fans with the square housing from Radio Shack. You have to wire them up yourself with a little switchable lamp cord but they are quiet and pump out a lot more air than the ARC internals do. I have one fan blowing into the armoire at the bottom through an access hole and one blowing out at the top of the shelf area. This "push-pull fan system" works beautifully as the inside of the armoire with the front doors closed doesn't even get warm.

I think that it'd probably work just as well with one fan but haven't tried it. Originally I was looking to maximize airflow through the component area...

No Fans on the D-115. Mk II is much better, For $1500.00 it had better be a MK II. and even that price is high ,unless it is Mint +++ and the tubes are new. Aragon makes a very good product for solid state, but the ARC is gonna sound ,as usual, more real. Wish it were'nt that way, I would love to not worry about tube wear ,bias, cost, quality, get the point....good luck!!
That D-115 idles at 400 watts. That is a lot of heat. It is rated at 100 watts which is quite a bit of power for a tube amp. Tube and component life would be shortened if your only avenue of ventilation is from the front and back of the cabinet. If there is an option to place it on TOP of the cabinet it would be the way to go. As Reprince notes, I would certainly look at the compatability of the ss pre-amp with a tube amp first before committing. The ARC should provide long term enjoyment and retain its value as well. As Frap notes, it better be a Mk2 for that price. I currently use one in my system and to help dissapate the heat and extend tube life, I have removed the black cover.
If you can find one, get your hands on a Audio Research 100.2 solid state amp. I have one and I love it. This amp has the great resolution of tube amps without the problems that you are concerned about (overheating in your rack). The amp does run warmer than most ss designs, but not nearly as hot as tube amps. This amp has truly amazing sound, but they tend to be hard to find on the used market. Good luck on your search