No you don't need to upgrade the stock intank pump. It makes a great lift pump to feed a surge tank and will flow alot as its basically under no pressure. There are many options for surge tanks and set ups. You can spend as much or as little as you like. Are you going to be running e85 and what sort of power are you chasing? Best to go overboard on the fuel system as you always end up going for more power later down the track. Cheaper to do right once than re do it 2 or 3 times down the track. I attached a pic of the setup in my tornado. Iv got a Herrod e85 intank module feeding a tray mounted surge with Teflon lines, 1x044 and a aftermarket stainless cleanable filter. Running to a plazmaman rail and turbosmart 1200hp regulator. More than enough for the current 400kw on e85 with the ability to add another 044 or a better pump if I ever build the motor. Jet Turbo is a great bloke to talk to regarding fuel systems and he can source aftermarket parts for a great price.