I've been driving Bimmers long time and this is the first time I feel like this. About 8 months ago I bought 2000 323ci w/ no problems. Right now it makes funny shake and noise when I drive 20miles an hour if I go more than 25-30 no shaking. Dealer said its front control arms, another dealer said because of the tires and alignment. ONLY SHAKES between 15 to 20 miles. Any ideas why?