personally i like NA cars. I can tune the hell out of webers since thats what i mainly use and grew up on. How big are the webers? The motor choice would depend on what the guy did to your tranny. Turbos like load, thats how they build boost. If your tranny is to tight the turbo motor might not feel any different than the NA motor. I like running short gears in the sand, like cruising 3rd gear and running in 3rd and 4th since they are the strongest gears in the box.
Carbs are easy to tune once you get them down. The biggest thing with dual carbs on a VW is the linkage if your linkage is sloppy and not equal then your carbs will never be right. They will pop and the motor will run very rough. I always start the car with the linkage not hooked up. Set everything the same. The air bleeds i normally run about (2) turns out to start and the idle screw are turned in enough to move the butterfly are about 1/8"-3/16". That might not let the car idle but its a good start. The linkage arms should not put any load on the carb butterfly levers, they should smoothy fall in the holes. once that is good then its fine tunning from there. More often than not the problems are from linkage not being correct. Webers get dirty also, they seem to get alot of crap in the jet valleys. Dellortos are the worst unless they are fixed to move the idle jets.
As far as the rear end. Im not sure what you want it to do. If you want to mob thru bigger shit with out slowing down then you need more shock and a coil over IMO. if you want to drive it like a 9 car then i would change the shocks to a min of 2.5" shocks with reserviors. The reservoirs will help keep the shocks cool which keeps the viscosity consistant longer, heat will kill a shock and give it a very squishy feel. The torsion bars in your car are another big thing. VW made a lot of different length bars for the rear. i like 28mm long bars out of a bus. They allow the car to ride smoother longer. The torsion bars are fixed at one end and as the car cycles thru the travel the bars twist more and get tighter, like a coil over. The longer the bar the more adjustment. You can set ride height with out the super tight feel that short bars will give you. Im not sure the size tire you use but that could be a problem if they are to big. I think you can get away with 31" i cant remeber if you can use 33" or not. Alot of 9 cars do not use stock torsion housings so they make the car wider to take up the length of the torsion bars.
hopefully this helps. If you need more info you know where to ask.
The Beav