laminatedlove@gmail.com wrote:
> Does any one know how the WRX TR differs from the standard Impreza
> 2.5i? Is the turbo the only difference? If so why not buy the 2.5i
> for around 18k and upgrade the hell out of it with 7k you save over
> the WRX TR? Assuming there are some differences besides the turbo,
> would it be impractical or impossible to make those changes after
> market?
>
> thanks
>

Compression ratio! Someone else may have the exact specs but IIRC the
turbo is somewhere in the 7's or low 8's. The 2.5L is up around 10.

You'd be hunting for gas with a high-enough octane rating to keep from
beating the poor 2.5 to death with detonation.

Changing pistons isn't cheap.