I know it's not a huge jump in from the 1fz-fe to the 2uz. I also have an 01 sequoia with the 4.7. Drastically different to drive. Way more power and much better mpg. Pulled a 21 ft boat for yrs with it, no problems. No way I would pull that boat with the 1fz-fe. I actually spent a bunch of time porting, polishing and blending the intake and exhaust on the 1fz-fe head. I got my 96 from original owner with blown headgasket. Rebuilt it with oem .020 over kit and even did crower stage 1 cams. Worst decision ever. Doesn't seem to run any better than a stock 1fz-fe imo. The 4.7 is a peppy little motor that has better power and is readily available. I totally thought about a 5.3 with a 4l80 or 6l80. Tuning and stand alone is very easy. At that point why not use an atlas. Part time, lower gearing, and basically for the cost of the adapter. What motor/drive train setup you running?