Aaah, don't worry about it. We have driven a lot of times topless in the rain, gone "puddle jumping" (see pic), and I've even stood on the rear bumper and pressure washed the dash board (hey, it was dirty and under warranty). The cassette deck didn't survive, but everything else was OK.
OK, now to explain a little so you all don't think I'm a complete chowderhead (Maine slang for a moron). I have taken the dash completely apart and installed various swiches for lights and whatnot. Taking it apart is fairly easy, and it's amazing how well built everything is. It's protected especially against water, so I have no problem washing it down (besides it's advertised with the "hose-down interior"!). The dash lexan extends below the steering column, the speakers have a foam shield to protect against water, and everything under there has a waterproof connection on it.
We have been caught many times in downpours without the top, and had to squeege off the inside of the windshield. We have also left the top off it in the summer and not worried about the rain, it's one of the reasons we specifically ordered the vinyl interior, it's "towel-dry and ready".
The TJ is actually the wife's, and she loves the power of the 4.0. Well, the pic was taken up to camp, where she and some of her friends like to get kinda wild and crazy. They'll power into a puddle (like the one pictured), and then stop in the middle and let the water shower down on them. This usually goes on for an hour of so, until everything is good and soaked. All in good fun.
We have also had it buried in numerous mud pits and trails, and completely coated the interior. Instead of trying to get every nook and cranny clean, one day I decided to "test" the hose-down interior, and since it was under warranty I didn't mind. It was at work and we had a pressure washer then, and between the rain storms and puddle jumping, I threw caution to the wind and just blasted it. The cassette deck didn't survive, but everything else was fine, no problems, and that was like 4 years ago (about 80,000 miles). We have also had the TJ in water 1/2 way up the doors, which are water tight, and there have been no adverse effects. We now have 118K on the odometer, and it's a tight as a drum, and while we don't abuse it like we used to, it hasn't shown any adverse effects from the early ordeals.