RE: Best 2.4GHz radio for water and land use.
The DX3S works fine for boats but like all 2.4 Ghz systems it is important to place the antenna well above water for good link. The SR3300T is well suited for that having the antenna on top and plus has telemetry hability. 2.4 Ghz is no problem with cars but since water is highly reflective of higher frequencies you need to keep that in mind! Metal,carbon fiber also will mask the signal.