I put in a gearvendors OD last winter , so far I have to say it was well worth it

Instead of 3200 - 4000 rpm on the highway I'm at 2600 - 3200 rpm ( 3:55 gears 235 60 14 tires ), gas mileage has gone up at least 2-3 mpg . On the drive to Montreal the gauge moves 1 marker instead of 2 1/2 marks . At 1.70 a litre or $7.00 + a gallon it helps , plus it's a lot easier to hear the radio or passengers .
It's also nice to have 1 h0D , 2ND OD and 3rd OD , you can really feel the difference in 1 OD and 2nd 0D really pulls . Will test it at the track this week , should cross the line just shifting into 3rd .
The install took about 4-6 hours , only needed a hammer to widen 2 spots on the trans tunnel , I'll take some pics of it installed this week and post them .
So far I think it is worth the money , a pleasure to drive on the highway , about 75% of my driving . Another thing is I can remove the overdrive to use on my next car if needed , so the cost can be spread out over a longer period . And the company is great to deal with , you can email and they get right back to you , or call and they are there to help , great American company . Worth every penny !