iPhone 3GS with OS 4.3.1-will it iPod in conjunction with Volvo stereo

Following the fiasco of finding that upgrading my iPhone 3Gs to iOS 4.2 killed its ability for the phones iPod function to connect with my 2010 Volvo V70 factory stereo (and then needing to endure an Apple (MS style) info black-out and wait months for the cure to the problem by way of installing iOS 4.3 on the phone) I am now confronted with the dilemma; do I upgrade to OS 4.3.1 ???
If you have upgraded your iPhone 3GS to iOS 4.3.1 and have tried it in your VOLVO please give details here; including year and model of your car.
If I have no reports, good or bad, over the next few weeks I will take the plunge blind and hope for the best! Watch this space for my experiments outcome.
iphone 3gs iOS 4 iOS 4.3.1 volvo stero