I have a Lenovo V570, Model# MWB01051808, Prod# 59305000 and SN# WB0209303. Currently it has 6GB memory (1 2GB, and 1 4GB module). Is it possible to upgrade it to 16GB ?

Like Scott said, Crucial's RAM website is quite useful. Unfortunately, the V570 doesn't support 16GB RAM. You can fit max 2x 4GB modules in it.

Check Crucial's RAM website. They are pretty good with telling you that.

I recommend always pairing RAM Memory UN match pairs by the same manufacturer and with the same speed. Also, I wound recommend only using manufacturer certified memory modules. You will get the best results using this approach. Be sure to wear gloves, or take other E.S.D. protective measures when touching ram and circuit boards. Reason-just one spark from a human fingertip can discharge a tiny, sometimes invisible spark that can damage your hardware.