Question about weapons

Maybe some1 can tell me that mean: Reg 7, 8 ... Weapons or Q 7, 8... Weapons?

req 7, req 8, etc. are the requirement for that weapon.

When you look at a weapon, it tells you how many attribute points you must have in that attribute line in order to use the weapon to it's full potential.
Example: A sword that says "Requires 9 Swordsmanship" will require you to have 9 points in the swordsmanship attribute in order for you to deal the full amount of damage listed on that sword.

q7, q8, etc. mean the same thing, its just a shorter way to write it.

To add to what RedDog91 said, all max damage greens require 9 os whatever attribute the weapon is tuned to. Any max damage weapon that requires 9 is considered by ANet to be perfect if all other modifiers for that weapon are also perfect.

For example: a shield that requires 9 Strength and has a modifier of +27 Health would not be a perfect shield, but add a +30 Health shield handle to it and it becomes perfect.

The text color reflects it's relative value to the merchant, it does not reflect it's real value. Almost everyone wants a gold weapon, however purple weapons can be just as good and save you a lot of money.

all except Shiro's Blades and Shiro's Sword, which are q13.
#nitpicking

and what weapon is batter (more valuable) with q7 or with q 13 ?

q7. Lower req is more prestigious, even though they don't generally give any advantages (the exception is shields, which are good at lower attributes because people can dump less points in them to get the full benefit).