Can anyone share some insight on Kombi front seats?

I have what appear to be standard low back seats in my 73 model. The drivers side has the adjustable rails and the passenger side has the 2 position lift up and slot in seat rather than rails. The seats are ok but are a bit old and dirty (the fronts are velour and the sides are vinyl so not sure if it's standard) and the springs are not the best.

What are my options to freshen them up a bit?

Are there any seats either from other models or later kombis that will fit straight in without modification? I'd prefer higher backs for comfort and safety. Either good enough to use or some crappy ones that can be refurbished.

2nd alternative is something from another car or some aftermarket seats but this will require mod plates to fit - has anyone fitted something in that works well and fits up relatively easilly and can tell me the make and model of donor vehicle/s?

3rd choice is reupholster the ones I have. Never having done this I have no idea on cost or how long it takes - any ideas? I want to retrim most of the inside anyway, the door panels are aluminium sheets so they have to go, the sliding door panel is missing, so I thought I'd redo the lot.

Tips, hints and ideas most welcome from those who have done such things to their Kombi.

The seats are correct for your year model except they shouldn,t have velour material seats.They should be basket weave vinyl on the seat and plain vinyl on the sides.1973 they did come out with headrest,with a zipper in them.From about 1975 the seats changed slitly,which where more thinner in the sides and the headrest where moulded vinyl with no zipper.The seats always looked like someones been sitting in them.they where designed more like the golf when they come out.From 1977 they changed the runners on the car,and the vinyl also become square weave pattern vinyl.
On both of my cars when I had brought them they had recaro seats and stratos seats.Both of them had holes drilled thru to the wheel well and where bolted on.They where not comfortable seats.I replaced them with original seats from a 1973 with headrest. To get them reupholstery in vinyl it would cost you around $200 dollars each.You still can get original vinyl from a TMI distributor. A good upholsterer should do it in a day but always give them 2-3 days to make sure. The frame can be A: sandblasted and powercoated .B: sandblasted and you buy pressure pack can paint the colour of you choose.C:Give them a light sand and repaint them your self.