Bridgestone runflats going at 17K - replacement ideas?

[bigx5er]

I noticed coming back from my 4K trip last week that my tires were getting noisy. The sound is actually worse on blacktop than concrete. Seems to be getting worse by the day now.

The tires are the 18" Bridgestones. We have Bridgestone RFTs on a 3 series a couple of years ago and had the exact same problem.

I searched the forums here and didn't see too many discussions on what people were replacing the 18" tires with. I do have a spare, so I'd really like to ditch runflats and go back to regular tires.

Interested in what others have done. Also -- can a full-sized spare fit in the well for the spare?