Best bang for buck ever. Installed mine few days ago and I can't stop grinning every time I turned on the injection switch.
Installed a Diesel Universal Stage1, with a 1gph pre turbo and a 3gph post intercooler. Ran 50/50 methanol mix.
With my trusted butt-o-meter, I would say a solid 30-40bhp or more increase. Reason: I managed a 10.2s century sprint compared to my previous 12.6s (before piggyback 16-ish).{Sprint test done on the same road, exact spot, same driving conditions} A standard 3.0 1KD-FTV auto can get from 0-100kph at an average of 11s.
People say, day and night difference. I beg to differ. It is more like an increase of 500cc in engine capacity. I have yet to test the top speed, but I saw 190kph which previously, was only achievable while going downhill

Did the installation in 2-3hrs, pretty straight forward, just follow the diagram. The hardest part is the route the wires from the ignition cable and installing a DIY backlit switch. Have to be gentle enough to push the wires through the engine's firewall, so as not to damage the existing wires.
My only complaint..... tank too small!! and there are some slight jerking between shifts after a long hard drive. Need to change to those high performance auto fluid. Other than that.... SUPERB PRODUCT!
Cheers!