Yet another brake issue

[jdbubb at ix.netcom.com (Dan Bubb)]

I've been trying to resurrect this POS 16V I bought last year and so far the brakes are trying my patience the most.
The problem is the brake pedal moves down quite far for the brakes to really grab. The action is progressive i.e. the brakes will apply with a reasonable amount of travel, but to get it to really stop the pedal moves down alot. Also, the brakes don't pump up, so I'm pretty sure I've got them bled correctly.
So, far I've replaced the rear calipers with A3 calipers and installed a new Corrado MC. Although I haven't rebuilt the front calipers I know the pistons move freely. Prop valves were disassembled and cleaned, there ain't much in there and the rear brakes bleed well (the fluid flow isn't blocked!) so I think that's alright.
Vacuum booster made a sucking sound when the brakes were applied so I swapped that out with a unit of unknown condition. It also makes a sucking sound with the brakes applied, just much more noticeable ;^). There is vacuum boost, but I don't really know how these things work and if they could cause the problem. No clue if the vacuum booster check valve is working or not.
Brake hoses are probably the ones that came on the car. My experience is that teflon/stainless braid hoses don't really make a lot of difference in how firm the pedal is, but that was replacing good condition factory hoses, so I'm wondering if anybody has seen a huge difference in brake feel just from swapping to teflon hoses.

My only point of reference is my 84 and my nephew's 86 which both have 16V MC's, 16V front brakes and stock rear drums. Both these cars have very firm brake pedals. Generally, in the past, this sort of problem is the MC, but this one is new so I'm stumped.

The one thing I do know is I'm really tired of the procedure required to bleed the A3 calipers on this car having now done it like 6 times!

Anybody got any ideas??
TIA
Dan