Rewiring the subs won't help.... a 1Ω load at the amp is a 1Ω load at the amp regardless of whether the subs are wired together in the box or separately outside the box.
As for pics, if you have a photobucket or some other image hosting account, you can link to photos on that account by clicking the picture frame at the tool bar on top of the posting window.
As for what the problem may actually be...
Depending on how the box is designed, one sub may not be cooling properly, which has already been mentioned. Ported boxes aren't too complicated but port location with respect to sub location is important.
With Type R subs I've seen bad connections where the tinsel leads meet the terminals and if that's the case with one of your subs, it could be causing the sub to get hot. You likely wouldn't have noticed it in a sealed box because you can't easily smell a hot coil when it's locked away in a closed chamber.
Lastly, as has also already been mentioned, "half way" means nothing. If the gain is half way and your preamp signal is above 2 volts, you are clipping the subs. If your bass boost is half way, you are most likely clipping the subs. If your crossover is half way, you're most likely asking the subs to play frequencies above their efficiency. If your infrasonic (subsonic) filter is half way, you're missing out on some really nice low end response. If all are half way, you're lucky the subs aren't already blown. ;-)