I have had the 302 model for almost 2 years now. I don't buy pads for it. Instead, I use polyfil. A big bag from Walmart is 4 bucks and lasted me over a year.
As for needing a signature, I don't remember.
Mine is still running well. I also have it set up in an open metal stand. It is just slightly audible if you get your ear up close to it but you definitely cannot hear it from a couple feet away. Be forewarned that priming these are a pain.