as an alternitive to silicone which i dont like to use on threaded fittings, I like to use liquid teflon, it comes in a can similar to the pvc glue and spreads on with the applicator provided, works great! non toxic too, flex pvc will give you the least amount of head loss as the curves are smooth, I prime and glue right away, all saws work but I do like my PVC saw, I also have pipe cutters for 1 1/2" pvc(steve), and they do go up to 2" but are only reasonably used for low pressure pipe, you would need to close them with a vice to cut scheldue 40pvc, if using hard pvc pipe using long sweeping elbows helps dramatically to improve flow, and steve's mention of using unions is as good as gold, you will hang yourself later if you ever have to take apart your plumbing and you didnt use unions...as said, test fitting is a life saver

edited for accuracy