What's the difference between a Rel t/9 & T/9i?

My HT setup uses a Bryston SP3 processor, NAD M22 and C-268 amps, with six KEF LS50s.  One of its Velodyne HGS-10s needs repair, so I think I'll substitute the KEF 10b for it.  

Given how little traffic there is on the LA freeways now, I'm tempted to make the drive from Montecito (AKA Santa Barbara) to LA to drop off the 10 and a 15 for repair.  George Meyer claims to be open for business.  His shop repaired the other 10 and 15 last year.  I've used the HGS models with SMS-1 bass management for decades.

Hello, 
This might sound obvious, but can you talk to the manufacturers and let them tell you how to sort this out. I believe I saw a YouTube video about being careful using the Neutrek connection with certain amps. Something about putting too much load on the amp. From OCD Hifi guy- Warning about this connection. This guy is very smart when it come to hooking up multiple amps and speakers. The thread will continue and you will see what they are talking about. 

At least for REL subwoofers, the high level input is designed with a significantly high impedance so it will not place any current load on the amplifier. You do need to be careful when connecting the high level cable to different amplifier types, though this is because of the different grounding practices of the different amp designs. As long as you follow the correct high level connection method for your amplifier type (class a/b, class d, balanced/differential amplifiers, etc.) there is no risk of damaging the amplifier by connecting a subwoofer high level. REL's service department can provide specific high level connection instructions if you do not know what class your amplifier is.