[Wynton]

These are at least some of the possibilities after you reraised with A4o.

(1) You might win on the flop, if it turned out TAG happened to have raised light and got no help.
(2) You might get reraised on the flop, because TAG might suspect you were on a resteal. So without help, you'll just fold.
(3) Same situation as last, except this time an Ace falls. Your hand could be good, but if it is, you probably won't get a lot of bets out of TAG.
(4) Same thing last, except an Ace falls and your out-kicked, in which case you could lose a pretty nice pot.

I think these possibilities mean that your play is at least somewhat risky against anyone. But the most important factor to me is your description of the opponent as a good TAG, with pretty aggressive stats. That description is enough reason for me to think twice before getting involved with a marginal hand.

So, against this guy I'd fold.