Get it checked by toyota computer check. I had a similar issue, the software ran some tests and came up with short circuit in EPS. I got the motor serviced by an electrician in chah sultan RWP (wont recommend him he was lazy, annoying and useless) and the problem disappeared.
Dont put 14", else u will have to lower the tyre profile to match power, pick and fuel economy. If u lower the tyre profile the ride gets harsh and after a while suspension starts to make noises. If u just wish to increase the ride height just put 1.5" spacers in the rare suspension. if you still plan to go with the rims make sure the width of the rim is suitable to your car suspension. I did a lot of experimentation with a belta and ended up wasting money on expensive imported rims (which i had to give away dirt cheap in the end). Normally people dont go for rims because if a single piece gets damaged the complete set is useless.