It rained a fair bit when I was away & when I got back there was no water emptying out. Mine only does it after really heavy rain & if the car has been standing for a while.
Ill check this when I get my car back. It doesnt happen all the time though only after really heavy rain. I've checked inside to make sure that the water is not getting into the car but it does not seem to be. This problem is obviously not normal?
On my Blitz exhaust the right side is lower, nowhere near 2cm though & is only noticeable if you look for it. From reading the my350z forums the standard exhaust is the same.
Maybe if you put some pictures up we can see how low it is.