Forget the wet foot test. I would head down to your local running shop and let them check your feet, they should know best. You can try on the Kayano 18s and see if they feel comfortable. I over pronate and wear Kayanos and love them, a great shoe!
Always try a new shoe first and get a professional to check it.
Why not POLAR? They are one of the biggest and best firms in the world for runners tech after all!
For a runner, GPS is not that necessary. There are many sites which you can use to map your run when you get home (www.mapmyrun.com etc.). A foot pod is much more useful for anybody trying to improve personal bests. Information like Cadence and Stride Length are much more important than any location logging.
ALSO, Polar Personal Trainer 5 software is far more superior than, Garmin BaseCamp. PolarPersonalTrainer.com is likewise more superior to both Garmin Connect and Nike+.
There is a drawback though! Both the Polar software and web-site are considerably more difficult to use (just takes time). Nike+ has that very childlike interface and Garmin is just not as comprehensive as Polar.
Polar also have GPS add-ons, Definitely have a look at them (RS800 is amazing) GPS is NOT the be all and end all.
P.S. You also won't get a better heart rate monitor including R-R (HRV) recording.