Courtney,

Thanks for your question! The Contour Shell Pant is simply that - a shell of fabric (wearing underlayers/thermals recommended for colder days). The Insulated pant will have an 80 gram fill of insulation throughout, keeping your legs much warmer than a shell, while on SNOW (could be TOO warm on a Spring day)! Thank nomis for the inseam venting to keep your body temp JUST right!

Yes, a Large would be fine...

I hope this helps... and ENJOY your season!

Ryan