for Toyota, the SR5 designation is a certain level of trim which varies somewhat depending on which vehicle it is on and what model year the vehicle is (the Tacoma is one of the vehicles Toyota offers the SR5 trim on, the Tundra would be one of the others).
Usually, SR5 includes options such as power windows and locks, keyless entry, cruise control air conditioning, single CD player and some type of upgraded interior. There may also be additional body moldings and those may be in color and a different rim/tire combination.
A PreRunner simply means the Tacoma has a 6 cylinder engine, but it is only rear-wheel drive.
PreRunners are not 4WD and are not available with a 4 cylinder engine.
The PreRunner will have a larger tire/rim combination like a 4WD model.
Prerunners usually have an SR5 trim package and may come in regular or extended cab configurations, depending on the model year.
Prerunners are easily identified by the Prerunner badging on the tailgate, or if that has been removed, by the absence of a 4WD shifter/turn dial in the interior of the cab.
A Tacoma may have the SR5 trim and may be a regular or extended cab, but be a 4 cylinder, 2WD or 4WD model.
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