The previous owners of my home installed and engineered flooring on the bottom floor. It's an oak from Anderson flooring. Now I want to add wood flooring to the upstairs. The style of flooring downstairs is ok, but I'd like to choose wider planks and possibly a hand scraped style. Is this going to look funny to guests? I was thinking of keeping carpet on the stairway. That way, the two floor styles are never seen together. Any thoughts or suggestions is appreciated.

The first thing to think about is if your idea can pass code inspection. The building code is for safety. The requirement for stairs of more than three risers is to have the rise and run of each tread to be within three-eighths of an inch.
Your home may already be non-conforming. Using the right material can enable work to be done to bring the home back to conforming to local and National Building Codes.
Protect your investment.