I've used Tony Banks to replace the cat back exhaust system on a manual MK3 petrol RAV4. It was Free flow. Was on the RAV4 for 3yrs.
Aside from the drone, the most noticeable difference from OEM was the loss of power/torque at low revs due to insufficient back pressure. In that time I've gone from doing 25k motorway miles a year to less than 5k. The lack of torque made driving the RAV4 more work than it should be, changing gears too frequently just to make progress.
The benefits of the free flow exhaust could only be felt at the top end of the power band, which on my car is around 4600 rpm (over 6000 rpm on a GS300?). Problem is that my commute now consists of 7 miles of stop-start traffic each way. The chances that I'm able get up to 4600 rpm are slim to none.
I went back to Tony Banks and had the free flow mufflers replaced with chambered ones. Drone is reduced and low rpm torque has returned.
None of the above is likely to apply if you have a 450H but it may be relevant to the electric motor-less 300 or 430.