Pros:

+35% Faster Sap Speed
+Releases a Sound that Makes nearby buildings confused (Sentries start firing randomly in to the air, dispensers stops producing ammo & metal, and the teleporters does only allow teleportations some times)


Cons:

+75% Noice
-50% Sapper Health
-Regenerates
-Regenerates for 20 Seconds



(I liked your idea of the Sapper regenerating)

Pros

+Twice as hard to break.
+Silent

Cons

-Turns off Sentry instead of blowing it up.

Pros:

+ Sapped Buildings will be disabled for an extra 5 seconds after the Sapper is destroyed
+200% Sapper Health

Cons:

-75% Sapper damage
-Owner is marked for death after the sapper is removed

+any word said after placing sapper will be repeated.

it would be cool if you could put music in game files and this item would play it when sapping.

Alright heres my take

Pros
[+] For each active sapper, You gain a temporary boost in defense
[+] If a sentry breaks close by to an enemy, they will temporarily be stunned by a loud burst of noise for a second
[+] Plays a Random Motivational song from the soundtrack

Cons
[-] For each active sapper, you will lose the ability to cloak for 5 seconds for the first +2 for each sapper afterwards.
[-] -10% slower sapping speed

pros
[+] the sapper reveals the building location through walls wiÞ a silhouette until the sapper's time is up
[+] the sapper is silent and does not alert the engineer

cons
[-] the sapper does no damage and doesn't disable the sentry