Figure I might as well chip in here - pun intended
When going to flash your car it will be pretty simple - Your car will be able to be flashed through the OBDII port in 15-20 minutes at a dealer so nothing needs to be opened or removed from the car. A Stage 1 flash is optimized for 91 octane while a 1+ flash is optimized for 93 octane.
The gains you will see from a tune will vary from +19-25 HP depending on your tune (1 and 1+ respectively), and a +11-17TQ increase as well over the range of the powerband. If you have any questions don't hesitate to ask or send me a PM. I'm here to help!
Found a dealer, and decided to give it a try. Appeared to be the best option available.
Went to purchase the Stage 1+, but it was not available for my particular series of ECU. So the loaded a Stage 1, and Unitronic said the would build the S1+ for me. ~4 weeks later I have been notified it is available. I intend to have it installed next week.
The S1, first impressions: performance up, acceleration a little smoother at tip-in, but frequently get a stumble or hesitation starting out. Also, my estimate is that fuel cons prion has gotten worse, rather than better, by about 5-6% (1 mpg). On three long trips of 400+ miles, with varying terrain, mountainous and relatively flat, and I am down.
So, on a whole overall performance, faster, smoother all the way through the power range. Minor issues that they said they would look at. Now I am upgrading to the S1+, all bets are off. Stay posted...