The LS kit comes with a longer downpipe than the GSR kit to accomodate the shorter catalytic converter. The LS kit also has the charge piping made for the higher throttle body entrance than the GSR. I believe the fuel managment system uses the same maps, but if you want to do it right, a stand alone ECU will be safer and will get you better power out of it.

But yes, the LS kit will bolt right onto your Type R because of the similar cat and throttle body positions. The Greddy kit is good for smog legality and quick spool-up but if you want better power gains and don't mind lag over power, look elsewhere.