The question is, for what models of Saabs has tolerance of ethanol blended fuel been specified and certified? Absent any specific manufacturer's claims, we attempt to deduce degree of tolerance.

My tentative hypothesis is that 16 valve Saab 900 from 1985 onward are essentially tolerant of E10 with probable issues with the fuel level sender, and cautions for fuel seals and the fuel return line from the FPR. Transition issues concerning ethanol's ability to strip accumulations of petroleum deposis are not a materials issue.

We assume certain possibilities. Not all parts of a model year may have the same degree of tolerance. Some parts originally expected to have been tolerant may have subsequently proved inadequate (seals come to mind). Perhaps (conjecture) materials changes were introduced without altering part numbers, and this must be considered unless it can be proven false.

United States Federal law required that model years beginning 1986 tolerate minimum [what amount?] amounts of ethanol in gasoline fuels [reference?]. For model years beginning 1988, certification of claims bcame mandatory [reference?]. Contributors to Volvo forums comments that prior to introduction of LH2.2 in 1988 Volvo models, ethanol tolerance was incomplete (or unclaimed).

The fuel system design and compenents for Saab 900 16 valves is highly similar among years 1985 - 1987. They are not identical. LH2.2 was introduced with the 16 valve in 1985. These components changed part numbers from 1985 to 1986: Filler neck; fuel pump screen; fuel pump mounting bellows; fuel pump check valve O-Rings; filter sealing rings fuel line from filter to rail; Fuel injector rail.

Table 1 lists all components of a 1986 900 Turbo that might come in contact with fuel or combustion byproducts.

component	material	fuel phase	notes	durability	info quality	part #
body paint at fuel inlet	[what kind of paint?]	liquid	occasional spills	unknown	conjecture
fuel cap	plastic	vapor	constant	ok	conjecture	4397048
fuel tank filler neck	plastic	vapor	constant	ok	conjecture	9335118 (1986-1994)
fuel tank	plastic	liquid	constant	ok	conjecture
fuel level sender (transmitter)	metal and [plastic foam?]	liquid	constant	probably vulnerable	conjecture	9361965 (1983-1988)
fuel pump	plastic case, stainless steel rollers.	liquid	constant	caution	conjecture. caution from VW boards	7526163 (prepump 1985-1988) 9392911 (pre-pump insert 1985-1986) 9386491 (screen - 1986-1989)
fuel pump rubber bellows	rubber.	vapor, splashing	constant	caution???	conjecture. It's rubber.	9367756 (1986-1989)
fuel pump check valve	brass	liquid	constant	ok	conjecture	??? (1984-1989)
fuel pump check valve O-Rings	???	liquid	constant	ok	conjecture	??? (1986-1994)
fuel line: Filter to Rail;	nylon	liquid	constant	ok	conjecture	8976409 (1986-1989)
other fuel lines (tank to filter; return line;	nylon	liquid	constant	ok	conjecture
fuel line: FPR to rail	nylon	liquid	constant	ok	conjecture	7564339 (1985-1994)
fuel filter sealing rings	steel with pliable seal	liquid	constant, at edges	ok	conjecture	4443883 & 4161162 (1986 - 1994)
any other fuel line seals? rail?	???	liquid	constant, at edges	ok	conjecture
fuel filter	steel and paper	liquid	constant	ok	conjecture	1389562 (1985-1994)
Seals at injector rail	steel with pliable seal	liquid	constant	ok	conjecture
fuel injector rail	steel	liquid	constant	ok	conjecture	7506611 (1986-1994)
fuel pressure regulator (2.5 Bar)	steel [anything else?]	liquid	constant	ok	conjecture	7564131 (stock 2.5 Bar 1985-1994) 7564123 (or 3.0 Bar stock to 1986-1990 16V NA)
fuel return line, rail to fender	ruber	liquid	constant	caution	conjecture. Concerns expressed on boards.
ELCD	plastic, valve, hose	vapor	constant	caution	caution from VW boards
injector	plastic and steel	liquid	constant	ok	conjecture	7560170 (1985-1988)
injector O-rings	[???]	vapor-air mix	constant	Caution	conjecture	7561210
intake manifold	aluminum	vapor-air mix	constant	ok	conjecture
valves	steel	liquid and vapor-air mix. Hot exhaust.	pulsing when engine is running.	ok	conjecture
head, cylinders, pistons	aluminum	liquid and vapor-air mix. Hot exhaust.	pulsing when engine is running.	ok	conjecture
Oxygen Sensor	Exotic	Hot exhaust.	constant when running	ok	conjecture	9392762 (1986-1990)
exhaust pipes	steel	Hot exhaust.	constant when running	ok	conjecture
Catalytic converter	steel, ceramic?, noble metal	Hot exhaust.	constant when running	ok	conjecture	7533540 (1984-1994)
muffler	steel, [what else?]	Hot exhaust.	constant when running	ok	conjecture	8822280 (1984-1994)

Notes

1. Stock fuel level senders using common gasoline have a high rate of failure, with failure being that the level marked is consistently less than the level in the tank, and with the sender level dropping discontinuously. It seems unlikely that the original design was incapable of handling benzene. I presume that ethanol added to modern gasoline is the culprit.
2. A concern frequently mentioned on the SaabNet.com C900 bulletin boards is that the injector o-rings may be susceptible to attack. Others note that since these o-rings are not immersed in fluid, rather they are exposed to an air-fuel vapor, they are unlikely to be attacked. I have found no first hand report of stock o-rings being attacked. I have no confirmation of this matter either way. The proper course is to test by soaking an o-ring in the proposed fuel and see if the material softens or changes dimensions. Some people have suggested using Viton o-rings. Marco Rubber posts a O-Ring Fluid Compatibility Guide that identifies the Viton compounds as being "marginal" for use with ethanol fluid. Buna-N is a recommended material for both ethanol and gasoline. It is unknown how Buna-N performs with blends of ethanol and gasoline, which are know to attack some materials more aggressively than either fluid alone.
3. The exhaust pipes, muffler and catalyst are designed to operate in an environment of hot water vapor and CO2 gas. When the engine shuts off and cools, some vapor condenses. The corrosive properties of ethanol and gasoline exhausts are essentially the same, that is, both harsh.