What's the year and model?
Is it just when the brake is applied, or does it shake only at certain speeds?
If the rotor shifted and some rust fell in behind it and the hub you might be looking at that causing your warble, wabble, shimmy or shake.
Strange if it's not since you only had the problem after installing different tires. (Did you see them spinning on the balancer -- I've had tire guys say there wasn't enough of a high spot to cause a shake and a sensitive front end still shake). Second opinions can be priceless. And costly.