ORIGINAL: mini-dude
No self-respecting REAL racer would suggest NOT using a temp guage.
Who is it that you think invented the use of temp guages?
It darn sure wasn't some backyard basher.
And I've never seen a
blind engine guru at the track
If you, or anyone - professional or amature, is relying on a temp gun to tune then you are not getting the best possible tune from you engine. I'd be willing to bet that there is no true professional racer that tunes his engine to a temp. As tweety and others have said, your eyes and ears will tell you far more about an engines tune than a temp gun ever will.
To the OP, the Picco is a good choice for the T-Maxx. It's very high on my list for the next one going in my Revo. I'd say go for it.