I’m replacing my rear sway bar with an adjustable whiteline sway bar.
Can anyone tell me do I have to pull out the cross member to get to the old one or can you leave it in place.

I managed to do this job on my own car without removing the rear X-member.
I supported the car on jack stands, removed the rear wheels, put a trolley jack under the middle of the X member to support it while I undid the 4 holding bolts. It was not even necessary to take all the bolts all right out but only enough to lower the X member an inch or so to gain access to the sway bar bracket bolts (see pic)
Plenty of WD40 and a ratchet ring spanner needed to remove them.
Took a bit of juggling to remove the sway bar, but not too difficult.
 
 
 

Thanks Redtarga I had a feeling that was how it was done.
 I wasnt sure how hard it was to get to the bolts.
 Now you've confermed it for me I'll get on to it.