20" Boss 338 with LowPros. Is a 2" drop too much for my 05'?
 

I had the same rims and tires on my 02' with a two inch drop and the front right tire scrubbed when I used the brakes the first couple of months until the fender well wore down.

I'm putting the same rims and tires on my new 05' gt, but possibly going to go with a 1.5" drop, or maybe 1.75".

Will those drops fit in an 05' model? What about a 2" drop?

No, sounds like the same drop you'd get with the Eibach sport-lines...you just have to make sure the offset is good and the tires allow for that kind of drop.

Below should work fine...
20x8.5 with a 255/35/20 up front
20x10 with a 295/30/20 out back

Yeah that's what I figured.

Side note, know any good lowering springs for relatively cheap? Preferably 1.75" drop?