So your car has what is called a dogbone mount so that the transmission case can be softly attached to the subframe of the car. It is basically a plastic ring surrounding rubber molding that surrounds a metal piece. This all sits up into the bottom of the subframe behind the transmission case. This metal piece has a bolt that runs through it to hold the actual dogbone, the metal arm that runs to the transmission case, in place. The factory mount is designed for ride comfort and to mininize noise/vibration/harshness (N/V/H). Unfortunately this means that there is a lot of play in the drivetrain. To many, the stock mount makes the car feel sloppy when you accelerate or shift. Hard acceleration can also result in "wheel hop."
So the idea behind an aftermarket dogbone mount
insert is to place a new piece of metal in the voids of the factory mount. This reduces the back and forth travel that the Dogbone is capable of, and greatly reduces drivetrain movement when shifting or accelerating.
After installing an insert, many say that the car "feels the way it should have come from the factory." Others however contest that the additional N/V/H that is produced from adding an insert is unbearable.
I personally only noticed significantly increased N/V/H while lugging the engine around 1200 RPM (which you shouldn't be doing anyway!) I also feel some while shifting into first sometimes, but it's not too bad.
Here is a video that shows the reduction in travel. You can see how stiffening up this movement will translate to some vibration to the cabin.
https://youtu.be/8SRDpOG2qdQ
Most people agree the 034 insert is the best low cost solution to the sloppiness of the factory mount.
https://store.034motorsport.com/mqb...golf-gti-r-8v-audi-a3-s3-billet-aluminum.html
I like mine but after about a year I decided to try out the revo mount, which actually replaces the whole bottom half of the mount rather than simply adding an insert to the existing mount. I'll be installing that in a few weeks.
As far as an easy, fast, cost effective solution, I say start with the 034 insert and see how you like it.
https://youtu.be/MEvzAjg_bJs
Note: many people will refer to this 034 insert as a "dogbone" or as a "mount" when in reality it is just an
insert for the actual mount for the actual dogbone. I hope this distinction prevents you from being confused when others fail to identify it exactly accurately. I'm sure I've been guilty of this plenty of times. Generally people know what you mean, especially with the 034 insert as 034 does not make a separate replacement mount or dogbone. Revo does replace the actual mount. And HPA replaces the mount AND the actual dogbone. Cost increases pretty dramatically, so start with the 034.