Weak points on an IRS Gearbox - Info needed

[Andy]

I will be uprating my IRS Gearbox, and I want it to be as strong as posible (within my budget). I do not intend to go the Porsche 5 speed route, but probably order one from www.VWSpeedShop.co.uk who supply Rancho transmissions.

Has anyone uprated their IRS box, as I have heard that the CV joints are something which needs to be replaced.

I am not sure I will be getting a Quaiffe, so will 930 CV joints fit straight on, or will I have to change anything else.

Also, what are the other weak points (apart from mainshaft etc) on the IRS box, any recomendations would be appreciated. Any cheaper but stronger alternatives (if they exist), apparently the CV joints on late type 2s are stronger, but are they compatible.

The gearbox will be used on a large torquey motor(type 1) with occasional drag strip use.

Any info would be appreciated.