I have a 2007 lexus SUV Do I need to put in high test fuel or will it run as well on regular?

I cut and pasted this from your owners manual.

Fuel types
Use unleaded gasoline. (91 Octane rating [Research Octane Number 96] or
Higher)
Fuel tank capacity
Approximately 19.2 gal. (72.5 L, 15.9 Imp. gal.)

Using a lower grade can be done, but you suffer in performance. The computer will automatically see spark knock and retard the ignition timing resulting in lower MPG numbers also.
Monitor your milage figures with each grade of gasoline and see what suits you best. Stay away from no name gas stations IMO. Remember to 'click' that gas cap tight or the CEL will come on and cost you.