To modify your street car with
go-fast race parts or other setups which hold little to no value to the driver, but is good for posing. This is especially
popular in the BMW E30 community. Similar to
rice, except trying to look like a track rat instead of a street racer.
btw, it can be used sarcastically by people who are actually upgrading their stuff for good reasons in jest towards the people who do it solely for looks.