Anyone using a Gear Venders O/D unit?

I have had mine in a 73 Dart for 4 years , The install was easy , I did have to cut a small section out of the tunnel and replace it . It was easier than trying to beat it. Spring for a new driveshaft, instead of getting your cut.
I run 3.55's and it transformed the car . I do take it on 100+ mile trips often and 70 mph in around 2300 rpm with 27' tires. Gas mileage increased around 15%. Clocked around 10,000 miles with no issues.