1) the shift from 3rd to 4th introduces some driver error - like I said in my earlier post, i'm trying to get rid of that; captain obvious 2)WOW differing weather conditions, ya don't say?! The whole point of the speed trial is to compare real life conditions. You want accurate results without your 'external factors' then have fun blowing $85 at the dyno each time you're curious if your car's STREET performance is up to par. 3)Anyone who doesn't have the software can DOWNLOAD IT, anyone who does not want to download it will not participate..