hello, i used to own a kia sorento 2006 model and i just recently sold it, so here's my take on the car. It has been generally been a very reliable car. In my 8 yrs of ownership, i only changed 2 injectors, so its pretty good considering i have also owned rextons before and i have change 8 injectors for that car in the span of 4 yrs. In my years of ownership these are the things that went wrong and you should look out for. The aircond compressor, the alternator, the rear shox and the radio unit. i changed the shox on my car to OME and the difference was very significant akin to light and day. The drive on highways was much more controlled and minus the floating feel, its is highly recommended that you upgrade the shox. For the aircond compressor, i would say its not too bad that it lasted me 8 years, but if compared to my office toyota altis, that cars aircond compressor has been running for 13 yrs without issues. The radio units fault would be the volume control nob, its really screwed up, even with very little use, as i use the steering controls more often. On top of that, the heater plugs would tend to get fried after 2 to 3 years, then you would need to replace them will fail. With regards to the ecu tuning or piggy back tuning, depends on which system you choose. i chose the ecu tuning route and the power has been amazing but there will be future problems with the gearbox. As the torque and hp will increase considerably, durability of the gearbox comes in to question. The increase in torque tends to make the gear box hold on gears longer, as if the torque is making it difficult for the gearbox to change in to a higher gear. But the engine does tend to rev freer and acceleration times improved, its makes the suv have better responses. I am not sure whether you are going for the ecu tuning or the piggy back route, but do be careful when you do it, as my ecu got fried 7 yrs on, whether it could be due to the tuning or not, i don't know, but definitely there were signs of strain on the gearbox, shifts where sometimes clunky towards the end of my ownership of the car. But after the ecu was replaced with a stock second hand unit, the clunkyness was much reduced and of course the power too, and i had to re-adapt to driving a less powerful car. So take the car you are eyeing for a test drive and if possible find out where the car was previously serviced and see whether any of the injectors have been replaced and also get the injectors checked out, as the injectors would cost alot to replace.
How much does it cost to replace injector? and what are the sign the injector is about to die?