I had ordered a set of Black Street Motor Mount Inserts. Received a Red Race Set instead. Said What the Hell! The top one was a snap with just a 18mm socket. Drove with just the top one installed for a day or two. Noticed no increased vibration or noises. Maybe a tiny vib. when I turned on the A/C but very minor. Installed the lower one today. Fooling with the splash guard getting it on and off was not fun. The two upper bolts were on and off by feel only as I couldn't see tthem. 2 of the 3 plastic push in bolts were not reusable so I replaced with short 1/4" bolt and nuts. I wished that I had a 12 point 21mm socket instead of a 6 point as there was not a lot of room for my 1/2" extension and wished for a little less movement when changing socket positions to try and get the required 85lbs of torque. I used blue Locktite on both bolts. I was surpirised that the vibration level increased very little with both inserts installed. A tiny little jolt when the A/C goeson and off and maybe a little more vibs at idle through the steering wheel. Maybe a litttle more exhaust noise inside the car but sounds good to me. I have not tried any full throttle launches but overall I see no trade offs for normal driving conditions.
I considered the HD Motor Mount Bolts but passed. I wonder is anyone has broken a factory bolt with - stock mounts - filled mounts - inserts - dog bone type? The HD bolts have allen heads and come with allen keys. I don't know how much torque one could push with an allen key but feel sure that it would fall far short of 85 lbs. I guess you could use a 1/2" bar with an allen tip but I even wonder if the inside of the bolts could take 85lbs with this small of a pushing area? I guess they must work ok but wonder why they didn't just use regular socket heads? If bolts can and do break maybe the $25 for HD bolts fro, Modern Performance would be worth it?

 

I've never had the factory bolt's break with my solid mounts.

 

Good call on going with the race inserts, IMO. They are better. Generally you aren't going to be snapping bolts on street tires unless you do burnouts or really hammer it with anything less than 350 hp.

 

I just finished installing my solid one, today & Tq it to 85ft lbs.. no snap. The factory bolts are very strong.