B&K Reference Amp-- Upgrade Work

So, I have a B&K Reference 7270 MKII amp in my HT system. It is a 7-Channel amp. The B&K amps are well reviewed and well received. It is a one heavy hefty amp. It weighs a ton.... While it works well, I feel that it is constrained to some extent in performing. I am using it to drive 7 out of 9 speakers in the system. The processor is Marantz. I have ran Audessey calibration multiple times to be sure that the output is calibrated well. 

When I bought this amp, it replaced two amps that were there in the system-- 2-channel Rotel and 5-channel Sunfire Cinema Grand. While the Rotel amp did not have balanced input, the Sunfire amp did. The B&K does not have balanced inputs at all. All its channels are with RCA connections. The amp sounds good, but from clarity, details, power, and overall sound view point, it certainly seems to be falling behind compared to the other two that I had. Every time I run it, it feels that it is not "breathing" well enough. It also runs significantly hot, if not warm. 

I am thinking to send it out for a refresh/upgrades. Any recommendations you guys might have? Please let me know.

Thank you.
Dhaval.