Let me see if I can get a picture here.
This is off of Wes Ingrams SPICA diagnosis website.
The PRV is located under the air box and on top of the front fuel filter canister. There are two bolts on top of the filter canister, the smaller holds the canister and filter, and the larger is the PRV, I think it's a 19mm size bolt head. It holds the banjo fitting that connects the return line from the SPICA and then to the gas tank.