I had a guarder PH fracture after an unknown number of shots... came to me used. I put in about 8k rounds on it.
Their springs aren't bad, but I also had one drop from 405 to 350.
I have a guarder infinite torque up motor as well... it seems to be a reasonable motor... not worth the price with shs and lonex motors being cheaper, especially since at the price the guarder motor is at, it's still only a ferrous motor.
I have not had a set of shs gears strip on me yet, though I think I lucked out with good bevels on both sets I have.
lonex gears are known to be on the soft side.
I futz with V2s, V3s and V6s. I could be wrong... but probably, most likely not, as far as I know.