I'm getting ready to change mine at the 16k and seriously considering doing 5.1, but have never used it b4. What r most of used guys doing? What r the important points to consider? I have a Mighty Vac and don't want to empty the systems, but pull the new stuff in right behind the old as I pump the old out.

5.1 stays cleaner longer. Higher boiling point. All good.

Unless you're breaking the system open for some reason, just pump through new fluid. No need to vac it.

Thanks. I'm just replacing the fluid to keep it fresh'n'new. I'll just pull the new stuff thru as i pump out the old.

The MityVac will be quicker and cleaner than pumping & bleeding, IMHO. Just be sure to bleed the system when you're done swapping the fluids.

FYI, I've been using Motul RBF600 racing fluid, with good results, cause the 5.1 seems to be hard to come by around here.

Seems to me that I read a thread on this forum a while back regarding the
use of silicone based fluids with the stock seals.
Is the 5.1 silicone like the 5.0; or have modifications been done to allow
for use in the stock system?

No, only the 5.0 is silicone based.

The 5.1 can be used in any DOT 3 or 4 system, with no ill effects. DO NOT MIX 5.0 IN ANY OTHER SYSTEM!

Can you tell me why I can't use 5.0 in my current system even if I evacuate the whole system first?
Seems to me it would be a much better product or at least paint friendly.

If your system was made for non 5.0 fluid 5.0 will ruin it. Even if you evacuate the whole system there will still be left over fluid.

5.0 and 5.1 do not mix, also I think 5.0 will eat the seals in a 5.1 compatible system.

Note: 5.1 is compatible with DOT 3 and 4.