Trans mount Cusco collar vs Whiteline insert
 

Don’t ask me why, but I already have both.

I am unsure which one to install / is better?

I figure they both work pretty well, which one has least NVH?
Or pros and cons to both?

This is a DD that I can’t stop throwing away money on... basically want a fun streetable DD, for rare track days.

I already have sti motor mounts, whiteline diff support insert, whiteline subframe bushing inserts.

I might be wrong, but IIRC whiteline limited gearbox movement just vertically, cusco's also longitudinally. Don't have these, have Perrin's, which works more like Cusco's i guess. I hear now slight supercharger-like gear whine at lowest gears (probably at others too, but drown in road/tire noise at higher speeds). It's quiet/not loud, so i ignore that.

Whiteline will add hardly any nvh. The perrin will add some aforementioned gear whine. You'll also hear the tranny turning over when you're in neutral. Easily liveable. I made the hole in the whiteline insert larger to accommodate the perrin, so I'm using both, which is cool I guess

I wonder if I could toss the lower big washer part of Cusco and use both. Trying to clean up a little drivetrain slop with least amount of NVH.