Originally Posted by hamster

It's even worse than that.

Per your second link 4 W/kg is about where an average _lean_ person can get realistically. Yes, 300 W at 160 lbs is 4 W/kg. But it does not mean that this guy can get to 300 W. That's because excess weight does not translate into extra wattage. The guy is 5'5", which means that his lean/skinny weight is about 130 lbs, and he can get to 130 * 0.454 * 4 = 236 W with training. For him 300 W is 5.1 W/kg.

Plus, the whole discussion is extremely vague, since he has no measuring equipment and his best estimate of his FTP is "120 to 170 W". That is about as precise as saying "I think I can bench press somewhere between 100 and 200 lbs".