It been done many times. Try ClubLexus.com for all the info you need of doing this swap. I think Mahdavi motorsports is doing one right now. Somewhat of the swap is easy cause a GS300 is the non turbo supra motor (2jzge) so that part should drop right in. The rest is modded driveshaft depends on what tranny your using. I think Veritek on here might have done the swap already.