Well Dano, it seems we have gottin off the track here:) You asked about Springs and guides.. lol.. That is something that I know nuthing about, but second had information tells me to stay away from Chinese sprngs..

I think I have read through Rich's posts or Vince's post that Crosman springs you can replace Gamo springs with. But since the Crosman springs are Chinese made I would not use them. To each his own.
For my experience with Turbo Tunes with CDT, he only uses Macari Springs in my Gamo's. Not had a bad on yet and I shoot allot. Also CDT makes his own custom guides and thingys which have held up for me since my first turbo tune. I don't know tha name of the materials he uses. Mabybe it is top secret. I don't know for sure...

But he seems to know quite abit about what works and what does not work because as he explained to me he has tried hundreds of different materials until he got it down to a nats A__s....
But anyway, I think CDT could give you more direct answer to your questions and maybe the library might shed some lite on the subject. He has donated quite a few articles..
Maybe CDT will chime in on this once again...hehe
Gene