Well mine is a US made engine and there is no room to do shit; so I am not fucking with it. Plus those fuckers would probably tell me I voided the warranty.
Just spray some interior detailer into a rag and wipe down those dress panels.
My dad used to have a CTS-V and I'd spray it all down without ever having a problem.
The V uses a roots-type blower. Plus it's covered. Nothing will happen if you pressure washed the crap out of it.
IDK why people think you'll ruin something if you get water under the hood.
There are 2 areas to pay attention to.
The intake. If you have and open element filter you can't get it wet, so cover it with a plastic bag. Most stock intake have openings that draw from the front bumper or fender, you're not getting water enough in there to threaten an issue unless you drove into a lake.
2, the alternator. Don't directly spray into it.
That's it.
You can spray the crap out of everything else and nothing is going to happen.