I'd say it's the best tuning aide you can buy. Car may feel good on the track. But lap times don't lie. One simple change may give you the 2 tenths that you needed. Or it could slow you down even more. You'll never know though without those lap times. I bought one for $110 from a friend. Then I won a new one at the Norrca Nats!! So I sold my old one to another friend for $100. It's a very good investment if you plan on being in the hobby for awhile.