I am using the nylon hose, just make sure it doesn't rub against anything that can wear a hole in it, and don't kink it. If there is a leak, then you can have a BIG mess...
I am going to get a stainless line soon. It's about $50-60
My pressure stays around 50-60psi when warmed up. I also have a high voume oil pump, but that should affect the pressure