If You are a fairly desent driver and have had some experience driving at more than just the local parking lot...Than you would probably notice a tremendous improvement in lap times...
Ok lets say you can make it around the track without hitting a dot, rail or cars for more than five laps than you can benifit from a tuned motor...
Also when choosing a motor tuner please take the time to get them from a someone who not only builds motors but races the same motors they sell, & will help you if your at the same race and or need help with other things RC related..
I would like to say that a good tuner will also
balance the armature....
THat is one of the things missing from the list below.
To balance an armature correctly is very important.
I have tried many tuners and alot of them are very good...
I am very happy with my tuner....It has taken a year of running other people's motors before I found the one I use currently and have found the customer service and tips are free and are worth more than the great motors he sells.....
Just my two pennies...
-Shookie <><