quattroworld

Yes, XP Mode is the same as XP when it comes to MS retiring any security patches. But, it doesn't matter to run Bentley, or VAG-COM or any other car software that may need Windows XP but not internet access.

The primary issues are with XP machines directly exposed to the internet and with browsing the internet. Your Bentley XP Mode VM doesn't need to have a port popped through your firewall, so no one is going to be coming in remotely to try and attack a known security exploit. And, you don't need to be browsing the internet from the XP Mode VM either, so your security risk is extremely low.

Lesser issue would be an exploit running in your host machine or on the network from another machine hopping into your XP machine, but if the rest of your network is protected, this is less likely.

Simply disconnect the network connection for XP Mode and all of this becomes irrelevant.

If Bentley has a built-in auto-update mechanism, connect the network to pull down updates (which would come from a known good server from Bentley), so no risk there, and then disconnect.

If you are using a copy of Bentley you "acquired" and need to get downloads for updates off random sites, then don't get those from within XP Mode. Pull them down into Win 7.