OP, I say if you're planning to go TT that soon, and you'll want/prefer 3" pipes to handle that, might as well go with the GTM setup, that way if you do go with the GTM TT kit, you know they will match up. Not to say others
won't, but the less unnecessary doubt there is, the more
you'll be.
Also, take into consideration you have the Nismo rear bumper... Which kits will fit with that vs the stock rear bumper... If any modification would be needed?
And as luck would have it... Check this thread out...
[Equinox] Install: GTM 3" Cat-back Exhaust