I have an Injen CAI fitted about 6 months now. I'll try post some pics later. I paid €350, delivered from the states, and at that got caught about €70 tax..
Fitted it myself, comes with a replacement washer bottle, front left splashguard needs to be cut to fit the pipe out, but pretty straight forward.
Found the difference very noticable straight away. No more heatsoak, pulls better, great noise.
As for water, we've had a lot of rain here in Ireland in the past 6 months. Never had a problem. My car is pretty low, and even at that you'd need to drive though a pretty big puddle to suck water in. You're going to be conscious of it and never that stupid hopefully. I took it off a few weeks ago to see if it had gotten dirty/wet with all the wet weather driving, and it hadn't. Where it sits it gets a nice cold feed from the brake duct, but the splash guard underneath protects it from any muck/stones/ and from getting really wet.
I'd recommend it as a good alternative to the Gruppe M.