What to do? Make STI fast and have slow DD or buy cheap fast car and keep STI as DD?

700 miles a week

20mpg STi
35 gallons of gas
~$140 ($4/gal)

35mpg Civic
20 gallons of gas
~$75 ($3.75/gal since it can run 87)

Saving $65/wk or $260/mo, probably enough to make the payment on a new or slightly used Civic…allowing you to mod the STi or sell it and spend the STi payment money plus any project car money all on a project…