you could use any k-jet or suitable aftermarket uprated pump really, just a case of getting it under the car somewhere and finding fuel lines to connect to it. some pumps are inline, i.e. just a bare metal pump with a fuel connection on each end. The MK1 Golf has one like this.
If you get an inline pump you'll want some kind of reservoir under the car to make sure the pump doesnt run dry, like I said earlier the MK3 Polo and later MK1 cab/rocco have one which will work perfectly.
Not sure what type of pump the saab uses, but for an easy life I would just buy a MK2 8v/16v k-jet pump & lines as it'll be a direct bolt on fit then. Lift pump can be from any MK2 GTI, they're all the same. Just have a different plug on top so make sure you get the right loom plug to match it.
as danny says the pump is controlled by the ecu via a relay, you want to do it this way to be safe. if you just wired it to ignition it wouldnt cut out if you had a crash. The 1.8t ecu will have a trigger wire you can use, as will the aftermarket managment options.
