I forgot to mention some of the things you might have to repair/replace on it, considering the age. They are great cars, but can be expensive if you don't have the tools to do a lot of the jobs.
Blower motor-may need new brushes(fairly inexepensive)
IF the blower motor itself is worn out(armature), you are looking at a minimum of $250(good idea if bad to replace fan, motor and everything-all one unit)
Motor seals could be a little expensive if you have to pay to fix.
Motor mounts, considering age, will probably need to be replaced. Mounts for motor and tranny will probably run you somewhere around $40-$60 for all three plus labor.
Flex discs may need to be replace because they are rubber and lose their workability over time. You will hear a drone/thumping noise a lot of times when you pull out or going into second. (guess-ti-mate-----cant remember) $30-50 each(2 of them-front and rear)
Ball joints may need replacing if you hear a screaking sound when you hit bumps at a slow speed, such as speed bumps or when you turn the car(putting the suspension in a bind). You are probably looking about $25 per joint(one on each side) and my mechanic charges about $85 labor to do each side.
Control arm bushings--not real expensive. Labor would be probably under $100
Headlight glass--if this is the frames that cover the fog lamps and around the headlights, I replaced mine myself with new ones that cost $32 including shipping.
alignment--it seems that there were never any adjustments on the rear and if for some reason the car was curbed or something and bent the underneath slightly, the only way to correct it is to have a pro-shop heat and bend to get it into alignment. I had to have my 300 done.
If the shocks are already replaced. This is good. Brakes--I suggest when replacing, using Pagid brakes. There is no squeak with these.
Hope this is not too long, but as you can see, these cars can potentially get expensive because with all cars, parts wear out. My luck has always been everything happened at once and I had a big bill repairing and replacing. If one thing happens and then another down the road, they are not real bad. Hope this will help you in your decision. But, if your current 300se has only just above100k, I would keep that one and fix all these parts on it versus the higer mileage car. Once you get everything replaced, you car will run forever.