I don't usually play cash games, so take this with a grain of salt.

As played I would 4b shove here.
1) SB is squeezing a fair lot here, as suggested by his fairly high aggression factor (if I'm reading those stats right, goddamn huds)
2) JJ is too strong to setmine with it
3) UTG, which is the one we should fear the most, laid down.
4) Stacksizes are wrong, as in if you bet anything meaningful, more than 1/3 of your stack should go in the pot making you committed anyway.
5) Your play can be interpreted as either weakness or trappyness.
6) Pot is already worth winning (?)

A shove in this spot should be very profitable, especially with the description that SB is a reg and knows a thing or two supposedly.
Some could argue that a smaller 4b is prefferable, saving you some money when SB is not bullshitting. But see point 4 (and 1).

Even better would be to 3b raise yourself instead of flatting in the first place.