I might have a bit of a problem coming up so I'm looking for input. I want to go to a Sram 970 cassette. The folks at Sram tell me their individual cogs are separated by spacers and should not be used on an alloy freehub unless the freehub manufacturer says it's ok. Shimano cassettes like Ultegra for example use a sprocket carrier and don't have this problem going on any freehub. With Sram's cassette you risk tearing up the alloy freehub much like people were finding with the soft Bontrager Race X Lite freehub getting beaten up by anything not Shimano/campy
So how do I rectify this or prevent it from happening? The obvious would be to stay with a Shimano cassette.
If that's the best way then my next question is: any opinions on Sram chains mixed with Ultegra cassette/derailer?

Or at least the chains... No experience with their road cassettes but their MTB cassettes work fine. As to your question about SRAM Chains with Ultegra cassettes that combo works fine... In fact, I'd take a SRAM chain over a Shimano chain any day on my road bike...

Shimano splines are very shallow and will not hold up well with individual cogs. Shimano's design was intended to work best with a steel cassette body. The SRAM cassette would work best with lower level hubs that still have a steel cassette body.

The new Shimano 10 speed hub fixes this problem, by making the splines deeper, but of course, it's not compatible with 9-speed cassettes.

I might have a bit of a problem coming up so I'm looking for input. I want to go to a Sram 970 cassette. The folks at Sram tell me their individual cogs are separated by spacers and should not be used on an alloy freehub unless the freehub manufacturer says it's ok. Shimano cassettes like Ultegra for example use a sprocket carrier and don't have this problem going on any freehub. With Sram's cassette you risk tearing up the alloy freehub much like people were finding with the soft Bontrager Race X Lite freehub getting beaten up by anything not Shimano/campy
So how do I rectify this or prevent it from happening? The obvious would be to stay with a Shimano cassette.
If that's the best way then my next question is: any opinions on Sram chains mixed with Ultegra cassette/derailer?

Well, I have not used sram cassettes on shimano freehubs, but I have used sram cassettes with shimano chains and shimano cassettes with sram chains. No problems either way.