For a legit, good running motor its going to cost you $3300+ shipping. Otherwise, its REALLY hard to find a good one for cheaper than that. I would recommend NOT running your LS tranny on a GSR cause that LS tranny will rob alot of power from it. If you are able to save up some more money, head over to
www.hmotorsonline.com and pick up one of their motors. Ive heard nothing but good things from them. As for finding someone to swap it for you, just post up a thread on here, and someone will be able to do it for you. I had juiced2ndgenteg do it for me.