The Plinius has good input impedance and input voltage sensitivity. The manual doesn't mention the db gain, you should ask plinius what it is. I think the Pass would be harder to integrate into a system due to its relatively low input impedence, but it depends on what preamp you going to use. Pass Labs website doesn't mention their input voltage sensitivity, you might want to ask them.
Unless you are prepared to buy used and sell the loser proceed with caution. You should really listen to both before you buy if you are going to buy new. Galen Carol Audio carries both lines. You might want to call him and ask his opinion. Maybe you could arrange an audition or fly to San Antonio to visit his showroom. Don't laugh at the idea, Galen gives good discounts and no sales tax unless you live in Texas.
Unless you are prepared to buy used and sell the loser proceed with caution. You should really listen to both before you buy if you are going to buy new. Galen Carol Audio carries both lines. You might want to call him and ask his opinion. Maybe you could arrange an audition or fly to San Antonio to visit his showroom. Don't laugh at the idea, Galen gives good discounts and no sales tax unless you live in Texas.