Working with a fellow a while back, he was very concerned with "trap speed" on long straights. He insisted that we "fix" the car so he could see a bigger number. (Yes, he was new to the sport).
No matter how much we talked I could not convince him that more speed at the end of the long straight was not going to lower his lap time enough to get to the top of the sheet (he was off by 6 to 7 seconds). However, thank goodness he was willing to look at the data from his system (which by the way he was using just for shift lights, speed and alarms).
Of course everybody here understands the critical importance of apex speed. Without it, peak speed means little. Wait for it, wait for it, okay, now the shameless plug.
However there are many facets of lower lap times hidden in the data. Everything from driver control to car response. It's not just a plug for webinars (by the way go to http://www.auto-ware.com/webinar_home.html for more info), but as a racer I've found nothing of greater impact than data analysis.
Racing is my passion, been doing it for 43 years, now. I must confess that in 1994 someone gave me Buddy Fey's book, I look at it for 2 minutes, said cool and put it in the book case never to be touched for 5 years. So, I understand how we all get to busy taking care of other things, but you just don't know what you are missing until you jump in. Come on in, the water is fine.