Not that I'm suggesting it's a good idea, but if you get it shipped as a present (purchased in the US) then I don't think they can apply the taxes.
Saying that though, the tax man is the last person you want on your back.
you have to pay duty + VAT, which combined for slovenia is 23.7%
A guitar is considered (some random numbers here, meaning the type of goods) etc etc, so for guitars, NEW or USED a 3.7% importing duty is added ..
thing is, if it was only duty and vat on top of the price of the guitar, it would be ok-ish.. i have to pay all of that on top of the shipping as well.
Also, i got things sent from the US labeled as gifts.. Boss stuff, gadgets, motherboards.. had to pay 5% duty and tax..
only way to kind of circumvent it, going the 'legal' way, is to have the guitar priced reeeeeeeeally low