Calgarian,
You've made some good decisions and are asking good questions.
First, my compliments on the thinking that lead you to the PS Audio phono stage. I haven't heard the GCPH, but having the foresight to acquire gain and loading flexibility to accommodate a wide array of cartridges was very wise.
Second, your Basik Plus is a low mass tonearm. It was intended for cartridges like the K9 and the Shure V15 types, most of which are MM's. MM cartridges tend to be light and highly compliant, and such cartridges prefer a low mass arms. If you're going to move up to an MC, it should also be light and of medium to high compliance. This eliminates the Denon 103 or any Shelter, for instance. I'll let you research the characteristics of the other carts on your list. Teach a man to fish... :-)
However, as one would expect in an arm intended for MM cartrides, your Basik Plus is a fairly entry level arm - as is the table it's mounted on. (That's why you're planning on moving up to a Scout.) IME it would be a step in the wrong direction to invest in an expensive cartridge for this rig. Some system upgrades can be done in any order, but this is not one of them. Putting a highly resolving cartridge (like a ZYX for example) on a less capable arm and/or table is usually a serious error. The cartridge reveals problems with the arm or table instead of revealing subtleties in the music.
Unless your current cartridge is worn out or damaged, my advice is to upgrade your table and arm first. You'll probably be surprised at how much better that cartridge sounds on a better rig like the Scout. In addition, you then need only concern yourself with choosing a cartridge to match one rig, the new one, rather than choosing a cartridge that will work on two.
Regards,
Doug
P.S. I thoroughly agree with the ZYX recommendations above, but not now. They are excellent cartridges. They are available both above AND below your price point. But buying one now would would put the cart before the horse.
P.P.S. Assuming your phono stage has enough clean gain, the low output version of an MC will *usually* sound better than a higher output version of the same cartrdige. Higher outputs within a model line are *usually* achieved by increasing the number of coils. Since those coils are all attached to the cantilever, the moving mass and inertia of the cantilever is increased. This necessarily makes it slower to respond to rapid groove transients. Lower output models have better dynamics and retrieve lower levels of detail - as a rule.
