fuel first, always fuel. running an 18g at 5800 ft isnt the same as running it 300 ft...so you have a little bit of a diff situation, your intake charge isnt at dense, so your O2 molecules dont bump around as much, so they dont create as much heat as they would down here.
with more fuel, you can prolong the necessity of upgrading the SMIC, im living proof of it. The only stock items on our powertrain are:
Block
Rods
Head casting
cams
valves
Intake man and ACC
turbo
exh. man
SMIC and piping
If i tried to list all my supporting mods, it would seriously be a 5 line paragraph, but the point is we are still running 14b and stock SMIC, and we have enough HP to carry us into the 12s assuming a decent driver (its a girl driver, ill leave it at that).
if you have an AFC and big injectors, you can always tune them down till you get that bigger turbo, but if you wanted to crank the boost on the STOCK turbo, you would still need that extra fuel. I have a friend w/ a bone stock car, and he melted a piston and scored his cyl wall because he ran 14 psi on a STOCK motor and fuel system...you NEED the fuel. And you can always tune out knock w/ extra fuel...within reason. Like, no matter how much fuel you add, you will have a HARD time running 20 psi on the 14b...believe me!
So, get the fuel first. tune for 0-3 knock count on 14 psi on the 14b and 93 octane. at that point you will be quite rich. then, once you get the FMIC, you can retune your AFC and lean it out a little since your intake air will be cooler, so youll gain HP from 2 sources: Leaner mixture and Increase airflow.
The T25 is a waste of time and not even worth working with unless you arent a tuner like most DSM'ers. a 14b is a nice step up and in most cases, is all youll need. Phil Beers ran 12.02 on his 14b...so do you really want to go faster than that? 14b is really a quite efficient turbo and flows good amounts of air to support the needs of MOST Hp junkies...its enough for me.
Btw, my next upgrades are:
Evo3 exh. manifold
Evo6 FMIC
custom hard pipes
2G TB elbow (waiting to be installed)
7cm2 turbine housing
i WILL run a 12.5 on my 14b, i promise.