I believe that I saw a recommendation on here to replace my stock brake fluid with Dot 5 but I saw a comment on a TV show that said that Dot 5 is not usually used in ABS systems. Will Dot 4 Plus do the job? Any safety or warranty issues with either?

go with a good hi temp dot 4 like atf super blue or comparable.

info on the different types of fluid.
http://www.gomog.com/allmorgan/brakefluids.html

Thanks! Any issues with warranty? Do you know?

ive never heard of any warranty issues with swapping to dot4. my clutch got better when i changed to dot4 too. it used to stick down sometimes under hard acceleration. i now have a separate res for the clutch.

Thank you