You really don't need to buy specialized speakers if you want them to survive some water here and there. Just higher quality regular speakers. The important part is what the speakers are made out of. See what the surround and the cone is made out of and buy something made from rubber or some synthetic material. Stay away from paper cones, etc. Make sure you use good quality connectors on the speakers also.
To explain my reasoning, I used to drive a CJ-7 that I put some Boston Acoustic 5.25's in the dash. I'd take the doors and top off and drive it everywhere...even on nights that it was pouring rain. Where they were at in the dash, they would get sprayed with huge amount of water and everytime nothing bad happened. They sounded the same brand new as they did the day I sold the Jeep.
'73 K5
Chevy good...Ford bad
