I have a few of those with music on them and they sound really good.
In 1986 that TDK MA-X was TDK's second best available cassette. TDK was no longer making the MA-R, but had updated the tape formulation and were selling the MA-XG as their flagship tape instead. IIRC, the 1986 MA-X and MA-XG used the same tape stock, with the big difference being that sexy metal frame shell for the MA-XG, which improved stabilization properties. The heavier shell does make a small difference, but you need really good gear to hear it.
The $25~ish and upwards ballpark value others have stated sounds about right for one with a pristine wrapper. Sadly, that tear might make a difference to a tape collector willing to pay a premium for it and limit your sale opportunities. Someone would have to buy that one with the intent of actually using it. As such, it would be interesting to see what it sells for if you list it. Regardless, I'd expect you to get no less than $20 for it as it is a relatively rare version of the MA-X. Just make sure you show the tear pic so that you don't have a whiny collector crying foul afterwards.
But, if you have a decent home deck, why not keep it and make yourself a killer mixtape using some of your favorite songs? See if you can hear the difference vs. SA-X for yourself? Beware, though... the tapehead bug might bite and the next thing you know you'll be buying a Nakamichi deck and tapes instead of boomers.