Goddamnit, i lost a big post i was typing. I guess i'll just go on the TL;DR section, and skip the math.
Power V bow has higher single shot damage capabilities than Mining Laser, except when used in scatter mode and really close. Don't have hard data for how much damage XR's Handgun does, but i believe the 13 hearts with a fully charged Power V bow are better than most of the bullets.
Sharpness/Smite/Bane V Diamond Sword has higher damage capabilities than Nanosaber, especially when combined with a Strength II potion, but doesn't have consistently high damage (pretty close when combined with the potion, though).
Vanilla Diamond Armor with proper enchants gives you better Damage Reduction than Nano Armor, because how vanilla armor mechanics + enchantments work. Makes you nearly as invincible as Quantum armor does, but doesn't remove status effect, doesn't give you flight, doesn't feed you, doesn't make you run faster, breathe underwater, etc... Although the last two are possible, with Respiration + TC3's Haste enchant.
My point? High damage and survivability are most definitely present in vanilla minecraft. With only vanilla items, it's possible to kill the wither in under 15 hits. About 11 or 12 hits on average if he never heals and you use max level equipment. Also, highest tier level of potions of harming is 9 hearts of damage, and they are thrown as fast as snowballs, possibly higher DPS than any mod item, except point-black scatter mining laser... Vanilla items are easy to obtain, don't require much in the way of infrastructure or resources, and they do offer you goodies.
One thing i never see anyone doing on FTB is building a beacon! It's an awesome thing to have around your base, regen health, dig faster, jump higher, run faster, deal more damage... Range is pretty good, too, and makes it easy to see your base from a distance
. Combined with stuff i said above, it's very much possible to kill the Wither under 10 hits, esp. taking critical hits into account. Make of all that what you will...
