LO calls bull
.
LM (or to be charitable, the f-16.net poster) is a muppet.
There has been informal discussion of a "Block 3" Rhino, mainly offering improvements in stealth. However, there's nothing to indicate that anything like a 25 per cent thrust boost (and has any engine ever seen a one-step 25 per cent thrust boost with the same airflow?) anywhere in the roadmap; nor, absent something radical like ADVENT, could it be done without affecting SFC. And nothing beyond the Block 2 Plus (current aircraft with some comms improvements) is even in the SH roadmap, let alone funded, let alone due to reach the fleet until 2009.
Unless, that is, the entire published roadmap is a cover for a black-world Block 3 that nobody has heard about, but the probability of such a thing has to be in the 0.000001 level.