Timecop wrote:
I still run my T2’s paired with external subs.

If you’re on the fence at all, get the T2’s and use the T7’s as side surrounds (as I have done), it’s glorious.

As Timecop says, and I agree, an advantage of T2's (current version is T2+'s), is that they have built in bass integration.

Your question started out asking about upgrading to T2's with no external sub vs keeping your T7's and adding 2 SuperSubs. Cost for two SuperSub X's is roughly $2,800, vs about $3,850 for two T2+'s. The advantage of the SuperSub option in that case is the bass slam the SuperSubs bring, at a lower total cost.

As you think about upgrading to T5's to go with the two SuperSub X's, adding roughly $2,200 to what you would spend, another option to consider would be to go with two T2+'s and ONE SuperSub X, for about $250 more than a T5/2 SuperSub X combination. The advantage of that is having in effect three subs with the T2's with LFE feeds also. Either option would let you move your T7's to surrounds.

As Timecop points out, lots of ways to upgrade what you have, and any of them would be a big step up, including adding just the two SuperSubs to your current T7 configuration! No wrong decisions there, all options are major steps up.

Have fun with your project!

Rick