Their latest units are Actiontec's GT701D. If they are doing a dedicated line it probably won't be necessary to have any DSL filters as it won't be connected to any other jacks in your home.
They call dedicated lines without voice a "delinked" line. It's a dummy line that will have dialtone and a phone number assigned to it for their records, but if you try and dial out on it, it just says "thank you for calling MTS".
If it's an MTS tech and not a contractor, ask them if they can call in to have it set to 7 Meg (Mbps). Their modems can "sync up" anywhere between like 3-7 Mbps, IIRC. If it's only at 3, it's still within their specs but obviously your speeds will suck.
When I had mine, it started out at 5 Mbps, and after a while dropped down to 3 Mbps. I think it was because the tech that put my dedicated line it didn't call the proper department to update their system, so at some point it re-established to the minimum speed. I have an idea why, but I don't know if I should say here.
They are phasing out their old modems, and will be reallocating them to rural communities. These new modems support the new ADSL2+ technology, so if you ever want a plan faster than Lightning (which is rated "up to" 7 Mbps) it will be capable of reaching those speeds. I think some of their older modems had a theoretical max of 8 Mbps, whereas the new ones are rated to 24 Mbps AFAIK