Hey man, there's no way you're gonna get max. output out of your amp on your factory alternator, you're gonna just have to decide for yourself if it's loud enough for you, tho.... AKA if you can get it loud enough for you, with minimal dimming/voltage drops, then you're fine.
But if you really wanna get the full power out of that beastly lanzar, get a new alt. Those opti's have really aggressive power supplies, they'll milk your elec. system clean.
Just don't ever turn your gear on at ANY volume without your car running (seriously) Those redtops are awesome batt's, tho. 3 year warranty, too. Had one in my GTI last summer, and when i sold that car for something more practical, i kept the batt. and built a system around it, and it's working great.
Good luck.
And ^^^ redtops aren't for racing, they just aren't made for full drainage, they're just a regular starter battery, just gel-core, and they've got really high cranking amps/ reserve amp hours for their size, and they're unspillable/don't make hydrogen while charging. Good stuff. 'Racing batteries' are usually just 16v power cells, to buffer alternator current, most actual racecars use 16v jump starters, to turn an engine with high compression. Once you get ~14:1 compression, starting the engine becomes tricky.