[Dominik]

I also mounted my motors in solid mounts, and the transmission in harder rubber since 25 years. I had the transmount solid once, but saw hairline cracks in the powder coating of the transmission crossmember which told me something!

I never felt the vibration were detrimental. My counter argument was that I increased torsional stiffness to the chassis. Apparently Nascar had a front motor plate and one at the bellhousing, and no rear transmission mount.

If you happen to have vibration at cruising speed (55mph?) I can understand that it is annoying.

On a side note, my differential was also mounted solid.