Yeah, pretty substantial across the board. However the louvers weren't the only thing that was done at the same time. Also installed an oil cooler and the exhaust was ceramic coated from headers to muffler, with some additional heat insulation in front of the fuel tank. I do have decent data though:
Trail temps:
Coolant - 201 to 204 (6 degree reduction)
Oil - 180 to 210 (30 degree reduction)
Intake - 135 to 155 (30 degree reduction)
Transmission - 150 to 180 (unchanged)
Highway temps:
Coolant - 196 to 201 (4 degree reduction)
Oil - 160 to 180 (30 degree reduction)
Intake - Ambient to Ambient +10 (50+ degree reduction)
Transmission - 150 to 180 (unchanged)
Temps will seem high compared to a 1FZ. LT1s are designed to run hot.
Anecdotally, there was also a lot less heat soak in the cab after wheeling for 15 hours straight yesterday. My DVS shifter console would damn near burn my leg by the end of the day. That's no longer the case - just warm to the touch.