Your DEX is incredibly low for a Sin X that's relying on double daggers.
If you're going MVP Hunting, you're going to want some more DEX than that, otherwise you won't even really be able to hit the bastards.
No offence, but if your friend has "experience" on RO, he wouldn't throw you such a ridiculous VIT-heavy build on a DD Sin X that really isn't useful for anything. Then again, I'd need to know more about your server.
I don't think this is a build that's really useful for anything, except maybe tanking due to your DEF. What's your server's max ASPD? Max stat is obviously 255, do you have the maximum ASPD available with 145 total AGI and 102 total DEX? Any Customs involved?
As for equipment, if you're just going MVPing with dual daggers, some Abyssmal Knight Cards will be incredibly useful to you. Try to find a Prof to make some converter scrolls for you as well, since certain elements will rape certain MVPs(such as Fire on Amon Ra, Wind against Garm, etc.). Try and build against the MVP you're going for. What element will numb its attacks to mere tickles? What are they weak against? What attacks should you be ready for?
Figure those out and your equipment will follow.
As for a build, I have one last question: The max stat is obviously 255, what about max LV and max stat points available? A max level 255/XX server will usually have 7237 stat points available, provided they haven't screwed with it.
Hope this helps.