#1
I know I can put some foam under or inside the springs to stop the vibration noise but...

I noticed today that they vibrate really loud when, and only, playing either the open D string or the D note in either the E or A strings. It won't happen in any other string or fret, neither if I play a sharp or flat D. Even more interesting, if I play the D note and then bend it it'll stop, and as soon as I get back to the note it starts right after.

I own this guitar (Squier Strat) for almost 5 years and never noticed such thing, perhaps a result from a setup I performed a few weeks ago?
'07 Jackson Pro Dinky DK2M (MIJ)
Squier Strat SE
Marshall Valvestate VS15R practice amp
#2
Is the vibration noticeable through the amp?
Guitar/Bass:
Schecter: Damien 6/Stilletto Extreme 5, Squier: Bullet HSS*, Washburn RX10*/WG-587, Agile Septor 727
*mods

Amps/FX
Peavey: Vypyr 30/Max 112 (200W), ISP: Decimator

Quote by dannyalcatraz
Understood- I waste money on amps*, too.

justinguitar.com is the answer