[clayfoushee]

A rather large percentage of BFG Radial TAs seem to be notoriously "unround", and the condition is exacerbated on a light car like Cobras. I could never completely get rid of the "shakes" even though I did most of the things you mentioned above. I switched to Yoko Avid STs and the problem disappeared.

There are many similar reported experiences here and on other Cobra forums.