This essay is for my Cobb Stage 1 reflash experience. I did it several days ago in anticipation of more extensive mods.
I had started thinking I just wanted a reflash because I missed how the GD STi seemed to throw you back in your speed and pick up insanely fast in any gear at any speed, something that the peaky, much narrower GR motor's powerband lacked.
Then you know how it goes, you start reading, thinking, researching and I am going to do a more complete upgrade. However, since I will do a stage 1 protune due to its greater safety along with the planned upgrades to an eventual stage 2+ goal, I figured the AP would be a good way to communicate with my tuner regarding engine management issues. I was also curious to try the gains from OTS Stage 1 vs protune to see if the protune truly is a "mid to high 300's hp at the crank" proposition as I had been advised.
So the installation was literally as easy as they said: plug and play. I would say it takes about the same amount of time to scrub down one wheel and make it totally shiny, but the reflash was far less effort, totally sedentary. Just don't open the doors or the process will blotto out your ECU. Keep the doors locked in case anyone might want to open them on you.
As far as the driving experience? Interesting.... interesting.
Initially the car drives wierd. Even after about 80 miles the throttle requires too much input for the reaction and this has been said by others as being common while the ECU is still learning the new tune. Heel toe downshifting and rev matching in the stock tune was one of the easiest I ever experienced in any car I have ever driven; now it's a bit trickier though it has improved somewhat. They say this can be protuned away. It's also hard to drive smoothly at low throttle input at low speed. Maybe this will go away but say you're at 1800rpm in 3rd gear, it's very jerky, and it's not a "fast, eager to go" kind of jerky, it's a very sudden on/off from throttle. This I don't like because stock it was one of the easiest throttles to modulate I have ever tried, I hope it goes away, but in any case, this can be protuned away as well.
It also makes a different noise. While definitely faster, the motor doesn't feel like it's as muscular. There are more higher pitched sounds from the wastegate, more flutter and very little extra turbo whine. It sounds less powerful and more wheezy from a noise point of view even though the power feel is mostly a lot better.
Power wise, it's definitely there; this is the part I (and the reader) was waiting to gloat about. I would say the car feels a little more powerful if you're immediately stepping on it but it still doesn't throw you back in your seat like the old GD's. In terms of throttle response, yes, there is more, the pickup is increased at all RPM's. What really makes the difference is going the distance: not just flooring it but flooring it and keeping the throttle firewalled. When you floor the sucker, it seems to waft forward with torque, and the longer you keep the gas down, the more it rushes forward. Instead of being a more "rev" motor stock with high torque peak, it feels more of a "torque" motor that wafts forward. The urgency is minimal, until you see the speed gauge and the backwards warp streaks of the cars that frantically disapear around you. You don't feel yourself gaining speed, you feel yourself at a speed that is higher than you think you should be, or is comfortable because you did not expect it!
It seems the motor has better low end across the spectrum, biggest difference is around 2500-4000 rpm, but regardless where, this sucker just loves to go, go, go, go gooooo!!!!!!!!. Wife noticed that the car "accelerates a lot more smoothly" and all of the bumps and bruises, hesitations and ups and downs of the torque curve now seem swollen away by a new, testosterone impregnated set of muscular torque curves. I'll repeat it again, it doesn't seem like a big difference initially, but the longer you flex its muscle by staying on the throttle, the more apparent the increased torque and HP feels.
I would say the power difference is subtle until you really get into it and let the car escape. Then its dramatic. 1st gear starts no longer bog or stall easily. Start off gently, and it will get out of the way, quickly, and only with say 1/3 throttle. Man, that's what I'm talking about!
2nd and 3rd gear pull very frenetically, much to the wife's chagrin. Now she feels thrown in the back of her seat and I see the effect (but I still don't feel thrown back).
Beyond that I would say downshifting is not needed. If you are in 5th, I would say even 6th on the highway, within a few car lengths you are streaking away at warp speed. Apply full throttle at any speed on the highway and it seems like all of a sudden you're not the one flooring it; it seems like the other cars shifted into reverse and they are flooring it at full bore away from you.
Overall I would rate the power difference as one gear lower, which is great. Once you're in the higher gears, you get the acceleration of one gear less, but in a taller gear that lasts longer. This is particularly awesome in 5th and 6th which used to not feel very good.
Another upside (or downside) of the power is that now the car is a little scary to drive. There simply isn't enough room on the highway unless it's clear because you will be going 65-95 in literally just a few heartbeats, and it keeps going. The rears of other cars loom on you quickly, but at times you feel the car shake its tail under power, more in the lower gears. There is also much more useable power oversteer in tight curves in the lower to mid gears. But overall now the car feels like it may need slightly taller lower gears and a little stiffer chassis and suspension, which is of course pending the protune. But the fact that now the car seems a tad overpowered is very telling of the power gains. Even though it doesn't feel as urgent and frenetic as a GD, I would venture to say that next to each other, particularly in the higher gears and past 100mph the GR Stage 1 Cobb OTS 93 octane map might just edge out a GR and, at least subjectively, be on par with a 335. Maybe I had better results than most; for me the longer I stay on the gas the faster it feels; just a stab of the throttle not so much, but boy, those highway pulls certainly rival a G37x, and that's saying something.
In other words, the motto of first chassis, then suspension, then tires, then brakes, lastly power is the best way to go. Cobb Stage 1 93 Octane for the GR STi's definitely is the testosterone shot in the arm the car needs. If it weren't for the potential knock issues, the car should have come this wayIMHO Cobb AP Stage 1 is pretty good, but problems can still exist. I think it's a nice jumping off point to a full stage 1 protune, but alone I'd be worried about knock, especially running a 93 octane map (which I am). The Cobb AP just makes sense if you're modding. Only real downside are warranty issues, but once the modding bug sinks its teeth in you.....
I still recommend a full protune which is cheaper and gives more power, but this is a nice intermediate step and the AP (even V2) is a good tool regardless.