TBH, I think they are a waste of time. I have one fitted (got it for cheap) just never bothered taking it off. What David said is true, but I don't think they make enough of a difference to splash out on one unless you want it for a bit of engine bay bling.
I had one but really waste of money and time but sold it so time only lol
too much vibration during idling through whole car!! wasn't my thing. imo it only holds the engine side ways but engine vibrates everywhere so... can't say it actually works..
It works if you know how to adjust the dampener. Obviously there is more vibrations through the cabin because it transfers(dampens) the vibrations through the whole bracket itself which happens to attach to the strut tower (car body)
If you load the dampener up against the engine and back it off a little I found it made getting into 3rd in a drag race very quick as I could slam it into the gate instead of miss it like you do when the whole engine shakes.
as Jpower says
its a damper and it can be adjusted. just have to set it up right. no issues with mine.. but saying that ive a poly gearbox mount so i feell all the vibrations anyway.. the idea of the damper is to give more initial torque when accelerating instead of the torque twisting the engine. thats why people upgrade the engine mounts too.. this also does the same job as the torque damper.