Are all; Impreza/WRX, engines famous Boxer engines? And lastly what would you say is too much milage for an used WRX Forgive my ignorance about this subject, I am really interested in all of this.
The 2019 models are all boxer engines and I believe the Imprezas have always had the same type as the rest, except for horsepower. The new model Impreza puts out 152 hp, the WRX has 268 hp, and the STI puts out 310 hp. I don't believe the Impreza has a turbo like the two big brothers. It has a similar exterior appearance to the WRX/STI, but might have a smaller wheelbase and different body features. You can get an Impreza in a hatchback too, but the WRX/STI used to offer a hatchback unlike nowadays.
How many miles is too many? That's hard to say. Lower is usually better, but it's been my experience buying used cars that it's more what kind of miles are on the care and the care the car had. In other words, a car with relatively low mileage may have been driven hard and not always maintained well which leads to potential headaches for the next owner. There are usually signs of neglect. When in doubt, have a used care checked out thoroughly by a mechanic you trust before you sign on the dotted line. I bought mine new mainly because I couldn't find a used one that fit my comfort level for one reason or another. I encountered too many that were heavily modded and the owner overinflated the price to compensate for the extra bells and whistles. No knocks against modding per sei, but be careful buying one that's been overly wrenched if you're looking into a daily driver.