Depends on the sender- some will mark the package as low value and gift/commercial sample so you avoid duty, but most won’t.Figure on payig the vat and import duty and a handling charge,my Cove Shocker cost me nearly £200 extra despite the gift marking because the value was high. Unfortunately since 9/11 the US postal service have a duty to report ‘suspicious’ transactions so the majority of the people i’ve dealt with in the states won’t risk sending too many ‘gifts’ for fear of the wrath of the authorities. If you are saving the thick end of a grand then think about flying out with a bike bag and an overnight bag, picking up the frame, stripping the price tags off and bringing it back with you. Of course with Chris king dollar for pound you could pop a few bits in as well for your mates to subsidise the trip. Do remember however that if its purchased in Manhattan you’ll pay their version of vat at aboput 7.5% i believe.
And like you I’m not interested in the ‘thats against the law’ brigade , until we stop getting ripped off over here then go for it.