Well when I calculated colony pods self payout time i didn't count sb purchase into equation
Neither did I; with the starbase cost you're looking at closer to 10000 effective credits of investment, and the payoff time for that is longer than 2 hours. The 48 minute number I gave ignores the cost of the starbase.
And 2 colony pod upgrade is much more effective than first since (i might be wrong on this)
Yeah, you are wrong. The second level gives twice as much benefit as the first level... but also costs twice as much! It's the most expensive starbase upgrade in the game, costing nearly as much as building an entirely new starbase.
Now once u are forced to build sb on every planet you can easily add trade port on sb as well if you really want to max your economy
The trade port upgrade is much better than the colony pods upgrade. It costs less (1000 credits, 150 metal, 100 crystal instead of 1800/275/150), and it gives higher returns (1.6 credits per second plus trade route bonus as opposed to 1.3 credits per second). Of course, I'd still reserve this one for expanding my trade route. If you already have a starbase standing, then the trade port upgrade is a worthwhile addition, but don't build a whole new starbase just on this one's account...
Darvin3, I'm curious as to why you chose 4.5-1 as your ratio...in my experience only the TEC have to generally purchase resources, and even then, its usually only metal or crystal, not both..
Raging Amish can take credit for the 4.5:1 ratio; he was using it before I was, and I completely agreed with him that it's the best overall constant for these kinds of calculations. It's not quite as good in the early-game where you often are selling resources, but it's very accurate in the late game where you're usually buying at least one type and rarely selling the other.
I completely disagree with your assessment of the factions. Once you move over to a primarily trade-based economy, you will always have a surplus of credits and will need to buy one (if not both) of your resources. In fact, I'd say Advent is in an even worse situation than TEC in this regard since they don't have any viable refinery and their extractor upgrade techs are more expensive. Now, I will agree that Vasari usually hits trade a tad later and with their scouts can maintain a better resource income, but if they grow large enough they will also suffer this same issue.
The basic premise is that extractors get less efficient as your empire gets bigger (loyalty becomes a factor), whereas trade ports get more effecient as your empire gets bigger (trade route). You can offset that a bit with refineries, but they have stacking issues and don't continue to improve like trade ports do as your empire expands. The net result is that for a sufficiently large empire, credit income [b]will[/i] invariably outpace metal and crystal income. So it's actually a fair presumption that you'll be buying a significant chunk of your resources in the late game.
I'd think that a 2.5-1 ratio would be more appropriate since the Vasari player is likely selling resources, not buying them...
Early game, yes. But late-game with a mature trade network and maxed out logistics? Not a chance. He's buying both resources, guaranteed.