Tire Load Ratings
The stock 20" tires are rated at exactly 1,874 pounds (load index 102). 1,800 pounds or above is a safe range. That's load index 101 (1,819 pounds) or above. (The 18" tires are rated load index 105, which is 2,039 pounds, but that's not relevant to your 20" rims)
Ride quality (rough/smooth, noisy/quiet) will be quite variable due to numerous factors, such as rubber compounds used, tread thickness, tread pattern, siping (get tires that are siped for better winter performance where you live), and tire pressure (for all but all terrains, which don't come in suitable 20" sizes, use the figure on your door sticker, which is 32psi for 20").
This next part is NOT universally true, because, as mentioned above, it's a variety of factors involved, but, generally, the quieter the ride, the tighter the tread pattern and worse snow performance. The rubber compounds are also usually a bit softer and wear quicker. Tires that are better winter rated also usually wear quicker (but again, not always, such as the Kumhos I run that have a very good tread wear rating). Tires that are smoother (vs rougher) usually have less tread and/or less aggressive tread patterns - again though, that's variable because rubber compounds affect that as well.
SHORT VERSION:
Becuse a lot of factors determine what you're asking, I'd review the reviews on sites that break it down by noise, road comfort, wet condition response, snow handling, etc, for each tire you're considering.
The stock 20" tires are rated at exactly 1,874 pounds (load index 102). 1,800 pounds or above is a safe range. That's load index 101 (1,819 pounds) or above. (The 18" tires are rated load index 105, which is 2,039 pounds, but that's not relevant to your 20" rims)
Ride quality (rough/smooth, noisy/quiet) will be quite variable due to numerous factors, such as rubber compounds used, tread thickness, tread pattern, siping (get tires that are siped for better winter performance where you live), and tire pressure (for all but all terrains, which don't come in suitable 20" sizes, use the figure on your door sticker, which is 32psi for 20").
This next part is NOT universally true, because, as mentioned above, it's a variety of factors involved, but, generally, the quieter the ride, the tighter the tread pattern and worse snow performance. The rubber compounds are also usually a bit softer and wear quicker. Tires that are better winter rated also usually wear quicker (but again, not always, such as the Kumhos I run that have a very good tread wear rating). Tires that are smoother (vs rougher) usually have less tread and/or less aggressive tread patterns - again though, that's variable because rubber compounds affect that as well.
SHORT VERSION:
Becuse a lot of factors determine what you're asking, I'd review the reviews on sites that break it down by noise, road comfort, wet condition response, snow handling, etc, for each tire you're considering.