I have had the Sperzels before and loved them but the price that AxesRus sell the grovers for is crazy. The locking mechanism is different on the Grovers, How does it work?
I have something of an obsession with locking tuners, so this might be a bit long-winded... :oops:
I see Axes'r'us have two different types of 3x3 Grovers, the 402 and the newer 106. The 402 set has a screw in the top of each post that you just tighten with a coin or the supplied tool to grip the string (very similar to the locking Schallers on newer PRS guitars).
The 106 set has a cam mechanism in the tuner post - you just pull the string through the post, hold the end of the string and start tuning. The string holds the outer part of the post in place, but the internal cam rotates until it grips the string - after that you can tune very quickly. No tools, no thumbwheels on the back of the tuners.
What I
don't like about the Grover 106s is that the tuner posts are far too long, so you don't get a good angle behind the nut (I don't know if the 402 set has the same problem). And they're much heavier than the Sperzels, which are made from some kind of lightweight alloy.
I don't know what tuners the Ibanez SZ320 has - are they the type with a "tab" at a 45 degree angle for the retaining screw? If they are, you'll need to drill new screw/pin holes for either the Sperzels or the Grovers.
I agree with Gingataff - my favourites are
Gotoh Magnum Locks. They use a fairly similar principle to the Grover 106s, but don't have the post-length problem. And you (probably) wouldn't need to drill any new holes.