BMW Repair: tires, vibration problem, tread wear

Question
I have '97 328 with 190K with vibration problem which increases with speed, and mechanic said I need new tires.  My question is at this mileage how can long can I expect it to go.  I dont want to spend $400 on tires, and it dies out in 10K miles.  Also, any suggestions on where to get cheaper tires?

Thanks

Answer
Tread wear rating is what you need to look at for tire wear.The higher the number the longer the wear.The performance is affected as well due to the tire being made of harder rubber.The lower tread wear numbers are softer and performance is better but they won't last for mileage.So its a hard question to answer,if you have performance in mind than you may have to bite the bullet,or just go midway and have a good time driving longer.Also remember to rotate your tires that gives you more miles of wear when done.