I have an LS3 and used 3/8 aluminum hard line directly off the boyd tank with the Stealth Pump. I've only go carted but so far but so good.
Aluminum was easy to bend and flare.
Be sure to support it every 6"s or so and I ran it inside the chassis rails. Vibration can cause havoc and it will puncture much easier than steel.
I also used an LS1 filter/regulator combo. It not only filters and is easily replaceble but also keepd the pressure right around 60psi and no other regulator needed.

I used the stock steel brake lines that came with the kit. I know a few have had problems with leaking but I didn't. Brakes are super firm with no leaks.