marine speakers & amp in Blazer

[fun in dirt]

Was thinking about installing some marine speakers in my Blazer. It will be topless most of the time, and thought this might help avoid problems if get caught out in the rain. Sounds good to me, but I don't know anything about them...what makes them marine speakers???

Also, plan on putting my amp (already have one, but not marine-if there even is such) inside the center console. How much air space does it need? Will it be a problem totally sealed - no air circulation???