boots of swiftness epic book 3.5

[Omey]

This boots duplicate your land speed and it has haste spell, that add 30' to your speed my cuestion is if i can add this speed for example : i have 30 bse speed and use the boots now i have 60 but if i activate haste now i have 90?

[Calthropstu]

Haste does not stack with itself. So no, you do not gain extra movement. Also, looking up the item it says it doesn't stack with other forms of increased movement.

[Omey]

If i have a monk level 18
30 bse speed level 18 + 60 speed no armor
Level 1 barbarian +10
+ 10 unearthed Arcana.. fast character that loose 1 hp per level
+5 feat in complete warrior

+ swiftness boots × 2

230 land speed ?

[Rizban]

You have to look at the bonus types (http://www.d20srd.org/srd/theBasics.htm#modifiers). If the bonuses are the same type, they do not stack.
If you have +20 Enhancement to speed and another +30 Enhancement to speed, you have a total of +30 Enhancement to speed.

Boots of Swiftness in the ELH specifically say
The wearer’s speed doubles (this does not stack with any magical or supernatural enhancement to speed)

[Calthropstu]

If i have a monk level 18
30 bse speed level 18 + 60 speed no armor
Level 1 barbarian +10
+ 10 unearthed Arcana.. fast character that loose 1 hp per level
+5 feat in complete warrior

+ swiftness boots × 2

230 land speed ?

As long as none of those say su or sp, or other magical nature, then yes.