I think he was asking about stiffer than stock mounts, not stiffer than AWR. RR-Racing has bushing inserts that use the stock mount housing (they work the same way as the AWR side mount inserts, just for the front and rear, too). Also, I've seen some people just fill the hollow parts of the stock bushing with window weld and similar products to stiffen them up a bit. Personally, I have the AWR front mount installed and the side inserts are waiting to be installed. The vibration is only noticeable/annoying at idle but it lessens as the mount breaks in. Also, the side inserts are supposed to lessen the vibration even further. AWR is top-notch and decently priced.