Hmm. I have had both 5 and 7 speed boxes but in the older generation of car.
The 5speed box was preferable overall. Diesel engines have a narrow power band, but a lot of torque within that powerband, a few well spread ratios are fine.
The advantage of the 7speed box is apparent at high cruising speeds. 80mph at 2000rpm, 120mph at 3000rpm. 40mph/1000rpm. The car I have is geared for 160mph before it hits the redline. In a 250cdi/220cdi which is not capable of these speeds this isnt an issue. However, at 60mph on a steep gradient it will drop to 6th gear, then into 7th. At 50mph its best just to stay in 6th as if in 7th, it will hunt between the two on every gradient change, whereas the old 5g can pull 50mph easily all the way at 5th. Makes it more smooth.
However, the tall gearing of the 7th gear gives it very good fuel consumption on the motorway and silence from the engine.
A 220cdi will be turning over at 2200rpm at 70mph and still silent but by 120mph will be nearer 3800rpm. The gearing is a little over 30mph/1000rpm in 5th. A 250cdi makes 370ft/lb torque, mine makes about 380ft/lb, 5 ratios are ample, and the car so strong, it does not need 7 gears.
Where the 5speed comes in to its own is that it changes gear less, feels like its less hunting for the gears. The changes seem smoother and faster in the old box. Its less clunky: read my thread about "jolts".
All sport models come with paddles, and paddles with 5speed is the best option.
