I have a 92 SSEi... and it does indeed have an EGR valve. More than likely the EGR-less models are exclusive to the VIN L models and not the VIN 1s.
As for the supercharger, the only potential problem that I could think of for anyone looking at buying one stems from incorrect information in the genuine GM shop manuals. They are printed to say that the SC is a sealed unit and cannot be serviced. Only later did they realize that you can and should check the SC oil level, and then they released a TSB for it. However, many dealerships and private mechanics don't check the TSBs. So the risk you take buying a used SC-equipped Bonneville is that, depending on where the car was serviced, you may have a car with 100,000+ miles on it that'* never had the SC fluid checked. Not necessarily a bad thing, but certainly risky.
As a side note, when you do get around to checking the SC fluid level, the fluid will smell REALLY bad. That'* perfectly normal, and is not a sign that your SC is in trouble.
As for my car, it'* 11 years old this month and has 119,000 miles on the clock. It still has the original SC, is 100% stock, and will open a can of serious whoop *** instantly on demand, and sounds damn good in the process. Having owned both a brand new 95 SSE NA and this used 92 SSEi, the 92 is by far the better performer, even with the 119K on the odometer.
Find a car lot that has a SSEi for sale, and take it out for a little ride. Experience the supercharger. You'll lose interest in that Taurus in no time.