Anti-magic

[PhoenixRivers]

We're talking about a wizard here. A +6 weapon is a trifling 72000gp, and if you just went +2 total, +1 and spell storing, its a mere 8000gp. I'll grant that contingent dimension door 1200 ft up is better, but an 8k anti grapple defense is something to consider. Besides, if you have access, drop a shivering touch in there. Even if it doesn't kill, it'll drop the dex below the threshold for the grapple skills, unless monk, in which case it stands a good chance of outright dropping him.

If you really want a grapple defense, go for a 40k Ring of Freedom of movement. The spell storing spikes still rely on winning grapple checks to damage. They're horrible tactics, as you will likely be outclassed in a grapple, and if you were going to win the grapple anyway, you don't need the "defense".

Further, spell storing items cast at the minimum CL for the spell, which means it's going to auto fail vs any SR of note. No. It's horribly bad. It's a waste of money, at any enhancement bonus.

Ring of Freedom of Movement.

Metamagic rods to play to your strengths.

Don't try to play your opponent's game. Make him play yours.