http://db.gamefaqs.com/console/psx/ file/final_fantasy_viii_time_ultimecia.txt

Piecing together those two will hopefully have provided a direct link to mine and Squall of SeeDs FAQ on R=U and such things on Gamefaqs.
It's a result of 2+ years of discussion(including on this forum), and although it isn't 100% complete, I can safely say it contains the most plausible R=U theory as well as all the logical arguments to and for. I say that not because I think I've done such a great job, but because of the great job by all the people I've discussed this with.

But to sum up my FAQ, the R=U theory simply isn't plausible. Simply the fact that it isn't mentioned or even hinted to in the Ultimania Guide for FF8 should be enough to tell us this, but for more reasons, check out that FAQ.

PS: If that link refuses to send you to an FAQ, go to:

www.gamefaqs.com

Search for "Final Fantasy VIII" --> Go to FAQs/Guides --> Find my "Time/Ultimecia Plot FAQ" (NOT the "Plot Analysis", which is a load of crap).