Is there any reason not to use the track key all the time?

 

I don't see why not. Ford may have given it a name that implies it is for the track, but in reality, Ford always tunes the car for too much daily driving in it.
What I mean is even their performance cars are too watered down from their true potentials because Ford has too much emphasis on street and daily driving.

The TracKey tune was initially held up from the public for so long even after the Bosses were already on the street because of EPA considerations. I cannot remember exactly when the TracKey became available to the Boss owners, but it was not until after Ford had worked out those details that would allow it to be used on the street.

Edit:
TracKey was delayed because of CARB. Cali might have objected the changes to the engine parameters and the elimination of skipshift.
But according to this article, FoMoCo apparently convinced that TracKey is still CARB compliant.
I don't know if Ford retweaked the TracKey tune or if it remained exactly the same as it was intended to be released at the time the very first Boss was to be sold.

http://www.stangtv.com/news/starting...-is-available/

In the end, TracKey is 50 state compliant and there is absolutely nothing wrong with using only the TracKey tune.

 

Better yet, set the tune for the normal key to like a 3K RPM limit and use that as a "valet" or young-uns key.

 

You can also turn on a Pit-lane speed limiter with the track key, simply by turning on the cruise control with the track key in. I found this out the other day when my car wouldn't go over 40mph . . . You can set it to whatever speed you want.

I have been driving with the track key off and on over the past week. It's awesome. I love it. For the most part it's a great mode to drive in all the time. There are, however, a few places I'd recommend the regular key. Slow traffic, and in parking structures. The track key changes the exhaust braking characteristics, so at slow speeds in 1st gear it's a bit more difficult to manage smoothly.

Also, if you're going on a long drive and plan to use cruise control, don't use the track key, as it turns your cruise control into a pitlane speed limiter .

Other than that, drive away with it engaged. I keep both keys on my ring.

 

I drove with it all the time until I changed the headers and had to tune the car. I loved the lopey idle, but the car seemed to drive a lot like my old 5.0 with the trackey which I loved.