Yes, it's saying that after 96 they did some internal changes to it, so I guess it has some flaws, but it's almost not happening. Astra F also using the same housing rack.

If I remember correctly, the Cavalier (on which the Calibra was based), was replaced by the Vauxhall Vectra in 1995.  I wonder whether they used the revised steering rack on the new Vauxhall Vectras, as well as the Astra F and late (post '96) Calibras.

Just got back from alignment, and as far as I know it's ok now, but as I expected didn't solve the problem. Now waiting for a reply from a power steering company I've e-mailed, to let it tested..

Frustrating.  Guess you just have to stick at it.  Do you have to take the rack off the car to have it tested, or can they test it in-situ?  Obviously, you don't want to drive the car too far with a possible faulty steering rack, in case you damage any other components, but is the car drivable, enough to get it somewhere to have the steering rack tested?

If I remember correctly, the Cavalier (on which the Calibra was based), was replaced by the Vauxhall Vectra in 1995.  I wonder whether they used the revised steering rack on the new Vauxhall Vectras, as well as the Astra F and late (post '96) Calibras.

All I can see is they point to these numbers:

Part nr ( steering wheel left ) 09 00 338 / (90 542 485)
Part nr ( steering wheel right ) 09 00 339 / (90 542 486)

C20LET ( Badkid ) coming soon, and will be dropped in the Cally later on.

Still have to fix the wobbling in the steeringwheel, but so far didn't get any reaction back from power steering companies. Amazing, they don't react back, when all they can do is make a living from you 

yes it will be nice to see it fix best of luck

The only thing I can find was excessive play in the right drive shaft ( vertical play ), I can hear an feel excessive " knock knock " sound. It's either the bearing or the middle cv joint. 

Interesting, if the wobble is intermittent (i.e. it appears at certain speeds and not others), I wonder whether the 'excessive play' that you refer to is amplified at resonant frequencies...

Now since I am going for F28 gearbox FWD, anybody familiar if I can use the same driveshaft as the C20NE, F16 gearbox, or need to go for a 16V driveshaft?

Good question.  I've no idea.  Sorry.    Quite apart from the different gearbox, the F28/6 box is designed to suit 5-stud hubs.   I wonder whether that makes any difference.  Is it worth fitting an F28/6 box to a C20NE and having to blank-off the prop-shaft drive?  Isn't the F28/6 gearbox also a slightly different length, so that you also have to change the engine & gearbox mounts? 

Interesting, if the wobble is intermittent (i.e. it appears at certain speeds and not others), I wonder whether the 'excessive play' that you refer to is amplified at resonant frequencies...

Me to... guess the only way to find it out is to swap driveshafts or replace the cv joint

Now I am busy to find a KKK-26 with a Porsche parts supplier 

Bart I had similar vibration issues on my last Calibra. I tried EVERYTHING. It turns out when breaking it last week I found the problem, it was the suspension top mount had broken. The bit just above the strut bearing had cracked and could move around, making the steering shake!