Urgot Maths: Manamune rush vs. Brutalizer

This post is for MashedPotatoe because I don't think he understand my point. Really this post is only going to boil down the damage because apparently thats what Mashed is all about, even though he says that's the only thing I'm concerned with despite my build being much more than just damage, I don't think he realizes it yet.
So let's take the champion
Urgot. Urgot gets 220 base mana on top of 45 per level. So this is assuming for both Urgots that they are equally skilled, have the same masteries, same runes, and hit the same CS. We'll say they hit about 85% which is a pretty good score but nothing like tournament play, probably your average 1400-1500 elo AD carry. So by 15 minutes you will have 475 starting gold + 1528 passive gold = 2003 passive gold. Factoring in farming, the maximum gold achievable is 5287 - 2003 passive gold giving us 3284 gold for hitting 100% cs. Take 15% of that off gives us 2791.4 gold from farming. 2791.4 plus the 2003 passive gold gives us 4794.4 out of …
So let's take the champion
