Superior Vision has been proclaimed as an excellent piece for most, if not all, Linebackers, since they need to see what the play is doing very quickly. Has something changed Darren?
A basic over view:
Anyway, the way shopping token equipment (known as Advanced Equipment, or AE) works is that you train on normal + shopping and get a shopping token. You use that token to refresh the Advanced Equipment store (in the 'Buy New Equipment' tab).
These equipment are generated randomly, and the quality seems to increase once you're over level 25. At any time you will be able to buy one of the three AE listed, and buying a piece will clear out the store of the other pieces so that they aren't available anymore.
Assuming you bought a piece, you now have a 'blank' Superior Equipment. It is considered a level 0 item, that is, the same level as a Basic piece of equipment that you can buy at any time. Just like a basic piece, you can upgrade it once you're level 8, and then you can upgrade it further every 8 levels after that (level 16, 24, 32, etc). That means you will add +1 X, where X is any of the basic stats. In order to upgrade AE, you need 8 bonus tokens and the correct amount of cash.
Lets say you bought a +2 Jumping AE. At level 0 (no upgrades), it will give you +2 Jumping. If you upgraded it once (level 8) for +1 speed, then that piece will give you +2 jumping, +1 Speed. Another upgrade (level 16) to speed gives you +2 Jumping, +2 Speed, and so on.
These pieces also sometimes come with bonuses to Special Abilities or percentage bonuses. Special ability bonuses are increased every other upgrade. I can't remember if the first upgrade increases it, but I know it's alternating upgrades. Percentage bonuses will be increased by 2% (I think) every upgrade.
So, lets say you bought a +2 Jumping, +1 Monster Hit piece. Upgrading it for +1 speed from level 0 puts it at +2 Jumping, +1 Monster Hit, and +1 speed. Another upgrade (level 16) and it goes to +2 Jumping, +2 Monster Hit, +2 Speed.
If you want to sell an AE that you've upgraded because you found a better piece or whatever, you will be able to get all of the bonus tokens out of it. So, you have some +2 Jumping, +2 Monster Hit, and +2 speed shoes (level 16) and you want to start upgrading your +3 speed +1 Aura of Intimidation (level 0) shoes that you were fortunate to find. You sell the Monster Hit shoes and get 16 bonus tokens and some amount of cash. You can then use those tokens and more cash to upgrade the Aura of Int piece.
That's about it for Advanced Equipment, if someone knows how the SA's and percentages increase or increase anything else I said that'd be great.