I run one of these and am happy with it.

However, I have to say I have become much less reliant on it...In fact, many times the gauge reads that the motor is happy at WOT, then I pull some plugs at the end of the track and it says otherwise...I change jetting and it picks up, and then the AFR readings are off from what is said to be ideal.

It's a nice tool to have, but reading plugs is MUCH more accurate imo and tells a whole different tale.

I have one friend who ruined a blown 302 in his mustang because all he did was go by the widebands on his MTX-L gauges and his megasquirt computer...If he had listened to me an pulled a plug he might have caught the problem in time.

If you can do without one, I would...It's not that big of a deal pulling plugs at the end of a run, but thats just my