As others have already said... It shouldn't really be an issue with 4 wheel disc even, unless you have a big rear brake bias, more fluid/pressure going to the rear brakes... usually about 70% of your braking is going to the front brakes, part of why the front brakes have a larger reservoir than the rears, less demand & usually smaller braking surface area, pucks or pads or even shoes on drums... The engine should overcome the slight drag of the rear brakes, especially in the water box, as long as your making enough power to run what your already running, it shouldn't be an issue... but a line lock isn't a bad idea either, especially once you get use to the routine of using one for launches & burn outs, it will isolate the front from the rear, once you activate it & hold the button on, for burn outs or launches... IMHFO it's not really necessary thou, if it was a manual trans car then I'd do a line lock for sure... good luck