The meaning of WRX STI is not very criptic, but it’s also not “well known”. Here’s the breakdown.
WRX stands for “World Rally eXperimental”. It’s the name given to the car that came out of the collaboration between the Prodrive British racing team and Subaru in the 1990s. The main difference between the WRX and a a regular Impreza is the turbocharge engine. But you also get more of everything, including all wheel drive and a stiffer suspension.
The interior has the rally-racing touch too: Different gear knob, different pedals, different dashnboard and RPM gauge.
STI stands for “Subaru Tecnica International“. It’s basically a better Subaru WRX with performance-tuned engines, transmissions, and suspensions. STI is the division of Fuji Heavy Industry’s that specializes in motorsports. This is the team that worked with Prodrive to develop the first Impreza WRX in the early 1990s.