I thought you use a Consult machine to do this?
You
can use a consult - which is what the dealers use. 9/10 times the dealers have no idea what they are talking about when it comes to aftermarket mods. They don't want to mess with the ECU because if they mess it up somehow, it is an expensive mistake for them.
Out in the tuner world, you use the UpRev Osiris cable, which is just an OBDII connector that runs to a USB connector. You can download the software for free from UpRev's site onto any laptop, plug in the Osiris cable and have access to the timing mod and a couple other items.
http://uprev.com/products.php
A little less than two years ago, one of the members here on IS was kind enough to ship his UpRev cable around the country - for anybody that wanted to do the +2 mod. That's when the majority of the members here did that mod, myself included.
If you do the +2 mod, you can run ONLY premium gas in your car 91 Octane or better.
Now that I have said all that, let me say this. IMO the +2 mod isn't worth it for the FX35 crowd, but it seems to have noticeable benefit (reported) for the FX45 crowd. My advice to any FX35 thinking about this mod is to wait and get a dyno tune instead - after you have finished doing your bolt-on performance mods. Getting a tune done will over-write the +2 mod, so if there is a chance for a dyno tune in your future, just wait.