I have a Tundra with a 5.7 now. I'm currently mid-trip on my from Utah to Alaska towing my 20 foot travel trailer. The 38 gallon tank is almost a must-have for a trip like this or jerry cans. Especially with a 5.7 getting 8mpg. Ouch. I would love the efficiency of the V35A. But it's great having 300+ miles of range towing.Yeah, as much as I would love a giant tank, none of my Toyotas have had the option. However, I did experience an emotional roller coaster reading this thread since I have a deposit in on a TRD Pro. I guess I'll just have to bust out the Jerry cans for road trips. Maybe an excuse to invest in rotopax.