Have you looked at / considered B6 Bilsteins?
34-181539 Front
24-002967 Rear
The HDs (B8) seems to be more expensive than the B4s on your list.
Where are you getting your prices from?
I've just been pricing up some B6 dampers for a 940 wagon, and it looks like FCP Euro have pretty damn good prices on them. FCP's prices for dampers match the prices on this site (URL below) which is pretty competitive. Note prices quoted are in real dollars (USD).
https://www.shockwarehouse.com/index.cfm?mode=results&selected_model=4550&selected_year=1989
That site says $252 USD (about $365 AUD) + shipping for a full set of B4s to fit a 240... and you've been quoted $562 for the same gear. Nearly $200 worth of postage? It really pays to shop around, as you can see.
FCP also has the B6 fronts for $152 USD each, and B6 rears for $99 USD each. The advantage with buying from FCP is that you can order parts other than shocks to make the shipping cost justifiable.
I have B6s and King Springs in one 940 wagon, and they do the job well for me- a good ride / handling package, in my opinion. But what suits me may not suit you, so....