Jacob, I built mine with what I already had laying around.
Yea, mine is overweight. However, it still flys/floats just fine.
It also has vast amounts of spare power. And that translates to looong flight times if I'm not pounding on it.
I always fly outdoors.. so I dont mind the higher wing loading.
It would not do well indoors... too heavy, too fast.

Its up to you.
What they recommend is (of course) just fine.
Without doubt, their lighter weight set-up will in fact fly better (in zero wind) and cause less load and flex.

I have a few Dualsky 430 3cells and I have noticed that it flys lighter and better on them, but the run times are noticeably less.

Its up to you... just know that it will tons of fun either way.