I don't really see how dumping money into your character will help when literally the ONLY thing NX wise that would help is NX equipment like Cadet Badge and what not. Unless you mean gold buying well then that's the players own fault for giving into temptation for buying gold. You can't use GG's or anything else. So there's really no way paying real money would help you even in the slightest. You can have 18k def and 30k att and still get destroyed. This raid isn't about stats alone. It's legit about having the skill to back your stats. So if you don't have the skills to back your stats then you need to keep practicing. As you have seen people beat the raid then you should understand it takes practice.
One of the best players I've ran with is a staff evie and far from pay2win running around with less than 10k defense and around 40spd. Yet they are the one who usually lasts the longest and can literally 1 man p3 till the revive timer expires for other party members.
This raid is the single most enjoyable thing to come out of Vindictus for me in years and really separates the skilled from those who think they are all that just cause they get top deeps in raids with their stims and merc pots c:.