As an owner of an SPG. I'd say the cars look meaner, handle a little better. But for the money a stock C900 with mods is the way to go.
I plan on doing some drastic sheet metal mods and how many people out there would be appalled to cut up an spg??????
I for one think the stock C900 T16 is a great place to start especially if you plan to do all out mods like lower the rad, coil over suspension, etc.
The SPG's are considered much more collectable and valuble and with the start up expense (2k vs 200.00usd) makes for a lot of mod's for the money.
Now me saying all this in the early days of SAABing I wouldn't have modified anything and would have been totally excited and in love with a stock SPG. (dream car right)
Now, as I've gotten over the buying original SAAB parts from SAAB and restoring everything I've come to realize that SAAB did a great job but there is some areas that need improvement. This is where I'm willing to change now.
Anyhow, If you plan to stick with stock suspension, some engine, FMIC, boost/turbo/APC upgrades maybe some Koni's or Bilsteins, maybe different rims and tires than an SPG being a collecter's car is perfect.
More major sheet metal mods I think it more befitting to cut up a standard T16, 1st since there still plenty around and other since the value isn't as high.
I by the way will be cutting up my SPG for some Carbon Fiber fender flares at some point. But then again it will also get rid of some rust in the fenders that would need replacement anyhow.