I have a bathroom in a poured concrete basement with no way to exhaust "aromas." However, the 3" vent stack is right next to the toilet in a false wall.

Could I install a 3" Studor vent, and force feed it with a small exhaust fan? Or is the spring in the vent too strong to be overcome by the fan's meager pressure?

You may already be vented by the lavatory. Most bathroom groups are roughed in like this. Toilet connects to sewer main or the stack vent. Lavatory connects to toilet drain and runs a vent off the top the stubout tee out the roof or revents back into a dry vent in the attic.. The toilet wet vents through the lavatory vent and the tub/shower connects to the lavatory drain and is wet vented by it. This is a normal rough in and is acceptable both by local and state codes and also The Standard Plumbing Code Book in 90 percent of the country. Check your local codes.to make sure you're not in the excluded 10 percent.. The vent off the lavatory may be run out the roof or revented back into a dry vent in the attic or if you're
Reventing back into a fixtures dry vent you must make your connection at least 6 inches over that fixtures flood rim. If yours isn't vented like that you can install a Studor vent on the lavatory.

Could I install a 3" Studor vent, and force feed it with a small exhaust fan? If you put air pressure, from a fan, in the vent you would defeat the Studor Vent. The AAV works off vacume not pressure.
Good luck, Tom