if you have a warm and/or lush sounding phonostage or overall system sound, try removing the mat and placing the record directly on the brass platter. If you have a neutral to just shy of neutral try an acrylic mat. I am using a mat I received from Chris Thornton which is acrylic. I was the guinea pig for this mat. contact Chris at Artisan Fidelity or find another acrylic mat.
obviously mats are very important and can make or break a system. The stock silicon feet are warm sounding and lean towards a bit of lushness. I experimented with different combinations until I arrived at a balance which I loved.
The one one thing I can tell you is that I've never had a combination where the stock mat didn't absolutely destroy the sound and that goes for the original stock rubber mat which came with my SP10 mk3, I use a custom copper mat which I purchased from Artisan Fidelity.
The copper mat mat does NOT work on the GAE! It was immediately evident that this was a bad combo but to Technics credit I believe the manual states that if you use a record weight or such the mass should under a certain amount (would have to refer to he manual again) and my copper mat did exceed the recommended weight limit.
I think it was Mr. Fremer who recommended the Holger Stein mat. I may try that mat one day.
I for one do not use clamps or weights. Everyone I've tried has shut the music down on both of my tables.
That table and arm will tell you Everything with regards to the sound based on your decisions, it is very very revealing.
I can clearly hear the differences between feet, mats and head shells.
Experiment and listen deeply into the music. I find small ensembles with accompanying vocals to be some of the best music to hear these types of changes.