a diesel box would have really long ratios so probably would annoy you. it isnt any stronger either so not worth it from that point of view. if your old box is in good condition use that, fit a nice new 210mm clutch and your old flywheel and away you go.
Oh this assumes your old clutch was a 210, if it was a 190 or 200 one then as above but you want a 210mm flywheel from a MK1/2 GTI or scirocco. Some MK3 ones fit but make sure it has 2 dowel pins, the later ones have just the 1 and are heavier, plus they require a different clutch that wont fit your box.