It could simply be that the lubricants are 'hardening'. If it's straining as it
seems, there's the potential to damage the motors.

Graham

Sounds like you need fluid in your conv top resivor.   probably located
under your rear seat.  Check with local parts store or saab dealer to see
if you need a special fluid.  My 1992 just takes regular jack oil.  If
your worried that you will do damage just diconnect the power top and open
it manually until you get it checked.  The manual override is in your trunk
behind the passenger side panel. Ckeck you book to be sure.   good luck
papa

I have the same basic car and the same problem worsening since I got
it.

I would recommend checking the hydraulic fluid. The pump and reservoir
are under a cover between the boot and rear seat. There are several
bolts holding it in place, although they must not be necessary because
every time the dealer worked on it they left off one more bolt.
Anyway, you can pull the unit up with the mounting (the top must be in
the up position) and check the fluid level. I have never found exactly
the type of hydraulic fluid it uses, but have had great results with a
high grade lift (jack) oil. I must have a leak somewhere in the
system, but I can't find it. As long as it goes up and down in a
reasonable time, I'm good with it. It has never been quick.