gabage digger, I have owned new since 1998 the Siver Sabre uMax. I also own a Bandido II uMax and a Cortes.
The Silver Sabre uMax is an EXCELLENT unit. the chatter you are sometimes getting is do to unit having a "preset ground balance". In most areas this will be more than exceptable but in areas of high mineralization you will get chatter. The Bandido II uMax which was sold as 1 step above the Silver Sabre uMax has a "manual ground balance" to phase out those minerals that may interfere with detecting. The Bandido II uMax is an AWESOME unit and has been the goto detector for many people before the new series of "hot coil detectors" from Tesoro were introduced ( Tejon, Cibola, Vaquero ).
As far as the warranty being applied only to the original purchaser, this is definitely the way Tesoro has it written within their warranty specs. In real life practice though Tesoro is known for being "very generous" and "committed" to the technology they put into their units.
As was said before, barring neglect such as drowning the unit, leaving in a trunk of a car in high heat ect. you can be expected to be treated VERY fairly if ever the need arises for you to send in the unit to be looked over.
You made an excellent choice with two very popular Tesoro units.
BTW, nice finds!
HH, Joe