OK i know they cause alot of vibration but is there nething bad about them besides that because i can get my front and rear made solid from a machine shop for free.
#51391, "RE: solid motor mount ?" In response to Reply # 0
They hold the motor still so you don't loose power to torqueing the motor, so this translated more power to the wheels. At extreme horsepower levels this can lead to damaging axles. But I'm talking about when you double the horsepower of the car.
And I think solid side mounts have a more detrimental effect than a solid front or rear.
Since it's free go for it, because it will rattle your teeth.