Hey, Montana, I did a lot of research (what little is available) and decided to try the Cobra Powrpro Autotuner. I paid about $530 for mine in October. So far, I love it. A local tuner here has installed a dozen or so of the PowrPros, and he says they're terrific, hasn't had any problems. You'll hear all kinds of opinions, but I'll tell you my actual experience with it.
Here in SoCal, I've heard quotes from $300 to $500 for a dyno tune after you spend $500 to $800 on a new fuel controller that has autotune. My plans are to modify my SG gradually; first pipes, then cams, high comp pistons, porting, maybe different pipes, etc, later, not all at once. If it works as advertised, I figured it will save me a couple thousand dollars within the next 2 or 3 years. And if I didn't like it, I decided I could live with the loss.
To begin with, this is my first real street bike, so I want to do all the work on it that I can. I'm not confident with my computer skills, so tweaking the fuel controllers' maps seems like a lot of work and time. I'm busy at work, and don't have much spare time anyway, like most of us.
Installation was a breeze. Took me a half of an hour, which means 15 minutes for someone with more Harley experience.
I read on other sites that, on Harleys, starting is harder with the PowrPro. I guess it's true. Before the PowrPro, the engine turned over one or two times before starting. Now it starts after turning over 2 or 3 times. In other words, it's barely noticeable.
The initial ride took about 10 minutes for the PowrPro to "learn" my engine. The throttle response was SO MUCH BETTER, it was very obvious. My SG felt faster at all RPMs, especially passing at 60-80 mph without down shifting. It may be my imagination, but I swear the engine runs smoother while cruising, too.
Stock, my bike would occasionally stall while idling, especially when hot. Mostly at stop lights or pedestrian crosswalks. Embarrassing. It hasn't done that since installing the Cobra. Stock, I also noticed a lot of decel pop, between 2500 to 1500 rpm. There is still some decel popping, but a lot less. I am trying to find out if Cobra can program a little richer mix in the "throttle off" position.
It has been reported that gas mileage drops initially, then improves back almost to baseline as the PowrPro "learns" your driving habits. This has also been my experience. I was averaging 38 to 42 mpg stock. It dropped to 36, and is climbing back up. Average about 38 mpg now. Two things might be affecting the mpg: the colder weather requires a longer warm up, and I goose the throttle every chance I get now.
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My bike runs much cooler now, too. At least 20-30 degrees cooler. I put on cat-less pipes, too, that helps.
Now, I have never ridden a stock bike, then felt the improvement after it was dyno tuned, so I can't say how this compares to TTS or Thundermax or Power commander. But so far, it performs exactly as advertised. Literally, plug and play.
I hope there is a way to completely eliminate the remaining decel popping. On the other hand, I kinda like it at the same time; it sounds really BadA$$.
The only drawback I can think of is the inability to alter the settings. But, I don't think there would be much change, even if you could dyno tune it.
Hope this helps. I'm happy to answer any questions.