They really sent me 3 samples for $3, shipping included. So, it costs you almost nothing to look a few combos.
Communication, quality and timeliness all great.

 

Even if you don't use the samples for anything else, they make great coasters.

 

Very cool!

 

My interior is black leather with CF trim, yellow gauges and yellow seat belts. Thought the black/yellow combo floor mat might be a nice accent...

 

Could be. I would order some samples (you will have them very quickly as they ship priority mail) and then put them in the car to see what looks best.

Black yellow, black grey or some others could all look good (or bad). For example, I was convinced that my 993 would look best with blue/white as the interior is blue and the exterior is white, but I ordered samples and the blue where it was the primary color of the mats looks too light to me compared to the interior and carpet so I went with black/blue and it looks great.

The yellow may be perfect and a match or may look off. Burn the $1 each (up to 10) and get your samples aka coasters. (FYI no affiliation with cocomats other than a happy customer).