900 Turbo 16S Purchase advice

Hello everyone, My first car, a faithful Golf II threatens to leave me now slowly after 6 years and I love to buy a Saab 900/1 Turbo 16S for more than half a year. Dream combination: 900 Turbo 16S (FPT), black body, beige leather, hand-operated gear, original Aero rims (or whatever these rims were called a three-bladed Trubine wheel at that time), Schrägschnauzer Why? I haven’t owned a Saab yet, but I’m with my father’s last two models (9000i and 9-3) grew up. Now to my questions and intentions: If I make the trouble to look for and maintain an (old) car like this, I would like to bring it up to H-approval, i.e. have as many years as possible to enjoy it. I am not a (hobby) screwdriver and therefore would have to let a vehicle wait away. Therefore my first question: Does someone know good workshops with experience at entsprec Hend alten Saabs im Raum Marburg-Gießen (Mittelhessen), besides the Saab-Zentrum Gießen and the company Eidam in Niederwalgen (near Marburg)? Who has had experience with the Saab-Zentrum Gießen? Do they have experience with old 900ers there? Have you been reading both in this forum for quite some time now, as well as at saab-cars.de and forum-auto.de and have already had a whole series of purchase advices. The typical pitfalls such as rust (drive shaft tunnels, wheel runs, underside doors, bonnet, trunk mboden,etc.)hanging sky, drained ignition lock, etc. are already known to me (in theory). As the car should last as long as possible, I step up the topic of bodywork and rust as the most important thing. My next question: Are there special tips for car body care, rust prevention etc.? Have already heard of cavity seals, is such a useful thing? What can a cavity seal do and what can it not do (is not a panacea…or)? I have also read about the possibility to upgrade LPTs to FPTs. The latter of course makes it easier to find a suitable car, because the 16S Turbos have obviously become quite rare at autoscout24.de or mobile.de. (According convertibles still seem to exist like sand at the sea.) Can you refer these conversion sets to FPT somewhere in the trade, or you have to work the individual parts somewhere (e.g. Ebay) individually What would be the rough financial framework for such a conversion? Who knows what about it? Now my most important question: Even if one internalizes the tips of the surrounding purchase advice (e.g. on forum-auto.de) as layman, to what extent is it not advisable to purchase a vehicle from private, since the risikio could possibly be too large to buy a sick barrel without a floor? Are there any experiences with you? Should one go to an established dealer, such as Fa He are the vehicle prices at Heuschmid actually justified in this regard? So, now still some detail questions: From which year of construction did the 900 airbag have and can one retrofit such a thing in doubt with reasonable effort? For example, did I hear that the vehicles allegedly even differ in the front window mounting, depending on whether or not there is airbag? Is there a possibility of blistering on the handgun deck Is it possible to retrofit wood optics on the amarture board and handcuff in doubt with reasonable effort, then the bubble problem would surely also be off the table? Under “air conditioning” I have to imagine a typical manual ventilation with heating in these years of construction rather than an automatic air conditioning system that can also cool in summer, right? Thanks in advance Nibohr