I'm also interested in having the rack mounts machined into the rack itself. Eventually a 20b will be in my car, just not as soon as you two.
Phil, I believe Gordon already has this same rack here in the states. If you live close to him I'm sure he'd be nice enough to let you check it out.
From the research I've gathered here are the pros and cons.
Pros:
Fast correction
Reduced steering input
deletion of entire power steering system 20 lbs savings just in the rack itself.
no core charge
different travel rates (increased steering angle)
free up power (no ps belt)
one less thing to leak
Cons:
hard to turn when stopped
cost