Nice to know many are now interested in Crystal Acoustics and are even considering for dedicated setups. T3 7.2 is indeed a wonderful package, but never had a chance to experience how it sounds with Marantz receivers. 7008 is a beefy receiver and it should handle the T3's really well. However, as many suggested here why not consider a THX certified ONKYO TX-NR929. The challenge here would be getting an audition together.
Well about the Onkyo receivers, until there is proper ventilation around it no issues at all. And hopefully the air conditioning (inside the dedicated room) should keep it cool.
All the best!