Thank you for the reply.
As far as reliability I have no concerns with the proper maintainence being performed, I know you are religious about keeping the car properly maintained.
The very slight loss of oil level is my only concern at this point.....yes the piston rings do tend to stick over time on this car and results in oil bypassing the rings and entering the combustion chamber, this results in oil consumption as well as spark lug fouling over time depending on the severity of the oil leaking past the rings and depending on how many cylinders it is effecting.
The ulitmate solution to this concern is to have the engine partiallt rebuilt....this is not a cheap option however one you may want to consider if you plan on keeping the car on the road for another 100,000 miles. During a rebuilt the pistons will be cleaned and new rings installed as well as the cylinder walls in the block rehoned to eliminate this solution.
THe only other way to reduce and possibly resolve this issue is a method that I have had moderate success with in the past. Basically what I do is rotate the engine to top dead center, remove the spark plugs and pour GM top engine cleaner down into each cylinder to flood the cylinder with very strong cleaner before storing the car over at least a 12 hour period, the cleaner will saturate the cylinders and break up the some of the deposits and help clean the grooves in the pistons that retain the rings. In some cases where the carbon and oil form a bond to the rings and the substance has not completely hardened this will allow the rings to break free once the cleaner is sucked out and the engine started. As I stated this is not a miracle solution, it's a possible solution that I have had moderate success with.
If you have no timing chain noise from the engine and no leaks then you can still get by on just topping off the oil for now, I recommend as always that you check the oil level every time that you refuel.
Let me know if I can elaborate on this or if you have any specific questions.
Aside from slight oil consumption this is a good motor, they hold up very well compared to the single cam engine used in the SL1 that had a list of known issues.
On a side note you opened a second question requesting me, there is no need to have 2 open question open, we can cover all your concerns right here in this thread. Thank you.