2 vs 4 seater 800 or 900?

I bought a 50" model the second year they came out but didn’t put a lot of miles on it before selling it, but loved it! I live in Michigan and I’m considering selling my dirt bike and buying another one next year. I’ll be riding mostly fire road and wider trails and 2 tracks. I don’t plan on doing any mudding, sand whoops would be my biggest concern, and my speed freak days are over. My wife and 12yr old son will be riding/driving at times. Doubtful all three of us will be going a lot, but it’s possible. I’ve been reading about the 4 seaters being a lot better through whoops and high speed stuff because of the wheelbase and stability. I recently rode in my buddies 1000 4 seater and was absolutely blown away how it handled bumps at speed! Simply Amazing! It’s really not fair to compare my old 50" to his though. So how would a RZR S 900 compare to the 1000 at 30-45mph whooped out sand and bumpy trails? Unfortunately I can’t really afford a 1000 xp 4 seater like his so I’m considering a 900 S or 800 or 900 4 seater. I won’t be buying until next year. I’m mostly concerned about reliability and handling on sand whoops and bumpy trails from 30-45 mph. I’ve been trying to read up like crazy but would still like some advise between models. For what I’m doing is the extra money for the 900 really worth it? Will the suspension be significantly better? Is there any glaring issues on the 800’s to be aware of? I’m sure power steering would be nice for my wife and son but I don’t think it would be a major issue for me. Any other advice would be appreciated!