[blau911]

The only difference between the 4 and 5 speed trannies on the LWB cars were the 3rd and 4th gears.
3rd gear was longer on the 4 speed.
4th gear on the 4 speed and 5th gear and the 5 speed were the same. Both cars had the same top speed gearing.
There are advantages to each gearbox. With the 4 speed there is one less gear to shift thru, and on the 5th speed, the rev range can be better optimised in 3rd and 4th gears.
I owned a 70 911T with a 4 speed, and after driving the 4 speed for a few days, the lack of 5th gear wasn't an issue. In fact, it took away the issue of potentially nicking reverse when shifting from 1st to 2nd gear.
By the way, what is a "euro" 4 speed?