I usually run 10W30 in my Maxima but I was wondering what would 5W30 do for my engine if anything? Do I need that added viscocity that 10W30 offers? Thoughts/opinions about brand and what grade of oil to use would be appreciated.

10W30 is probably right ->
 

5W30 is the recommended type for a stock Maxima. The only reason to bump up a viscosity grade would be if the engine ran a little hotter, which a SC'd Maxima certainly does (hotter inside the cylinders, anyway - more chance of detonation with a SC - must be hotter). I'd think 10W30 would be a wise choice.

Mobil 1 is a good oil. Very good performance at a reasonable price...I'd use that at minimum. Amsoil makes some awesome oils that we're finding out can be run for pretty extended drain intervals...well past 7500 miles. It's expensive, but if you can extend the intervals, it'll pay for itself. Mobil 1 looks like it can handle longer intervals as well, like 7500 or so, maybe longer. I'd just shy away from petroleum-based oils if you can avoid it, but if you do use them, drain at 3000-4000 miles.