Has anyone else used a procal on a 2011 3.8 auto with 285/65/18's, and have found it worth it? The tire size increase is not a whole lot bigger then stock.

 

I went from stock to 285/70/17 (same size as the 285/65/18 just with 17" rim) The larger tires are probably about on average 10lbs heavier each than stock and that extra weight comes into play along with the extra diameter. I have a manual and I noticed when I bumped up in tire size my "comfortable" shift points all moved up a bit in the rpm range. It wasn't a big deal at all but it was noticeable. As for the procal, it's probably worth it if you find a good deal just to make that small adjustment and also re-calibrate your speedo (it won't be that far off, but if you are OCD...)