Getrag 265/5 is a close ratio gearbox and has the same gear ratio in fifth gear as the stock Getrag 262 has in fourth gear.
So if you're looking to get some rpms down for highway cruising, the Getrag 265/6 overdrive is a much better alternative.
Both of these are common for 5-speed swaps in our coupes, you just need to know what you want to achieve with the swap.
Then there are several different diff gear ratios that can mix it up a bit, but your CSi should have 3.25.
Be aware that newer 265/5 and 265/6 gearboxes may not have the mechanical drive for the speedometer, but a handy person can add that to a gearbox that came without speedo drive.
Getrag 262 4-speed (stock)
1st - 3,85:1
2nd - 2,20:1
3rd - 1,40:1
4th - 1,00:1
Gertag 265/5 CR 5-speed
1st - 3.72:1
2nd - 2.40:1
3rd - 1.77:1
4th - 1.26:1
5th - 1.00:1
Gertag 265/6 Overdrive 5-speed
1st - 3.82:1
2nd - 2.2:1
3rd - 1.4:1
4th - 1.00:1
5th - 0.81:1