Is the 5th gear mod worth doing as I have heard different people speaking about it.
The answer is subjective......probably costs around £300 inc. labour
You may re-coupe this cost over a period of time due to an increase in MPG while driving in top gear......but
It really depends on how often you drive your car, the mileage you cover, the type of roads typically driven and the speed you travel at.
For me it's a win-win......I'm happy to plant my right foot hard under any conditions, but as I want my car to be around for a long time I don't abuse it.
My daily drive is >50 miles each way and primarily on flat dual carriage ways. I drive at around 65mph on these roads and therefore I have noticed better fuel economy and lower engine noise.
While driving at this speed, I find I have enough power to accelerate way beyond the legal speed limit, and at a good pace, should I need to.
However if your typical journeys are short, lots of roundabouts or hills or you drive most of the time at 50mph or lower, then the mod may seem like a retrograde step.
The car is less lively in 5th at speeds between 40 & 50, but at about 50mph you'll just be in the power band where the turbo is spooling up, so the car starts to perform again. On a flat road I can still comfortably drive at 35mph and accelerate with the traffic while in 5th gear.
Depending on how long you have owned your car, and how you drive it, your driving "style" may have to change.....For example, my previous TDi75 had standard gearing and I could travel through villages in 5th at 28mph without the revs falling below tickover (although this is not recommended anyway), but now that is not possible, so 4th gear would now need to be used to ensure an engine rpm above 950 (although I don't drive like this in the real world – I’d be in 3rd). There is a noticeable difference in the 4th to 5th gear jump, but I find changing up from 4th at about 2200 rpm keeps my car within the turbo-boost band for 5th gear, so I can still accelerate well.
Other factors to consider are weight. If you carry passengers, have heavy 17" wheels and the heavy OSS glass roof with a bit of weight in the boot, you may be changing up & down the box more than you would with the standard ratio.
So......in short......for me it works really well & I wouldn't go back, but for you...............??
Hope this helps
Cheers
Jeff