Sounds like you really want to keep the s13 around to make your own personal project and something you can smile about when it's all said and done. Keep the s14 as the daily driver, and enjoy that it's done up a bit (your current mods), and slowly work at the s13 as your track car.
You can pass smog with the sr20, it just won't pass visual. You just need to slip the guy some coin to make it pass visual, or know friends in the industry.
Up to you, sounds like you've already done quite a bit of work on the s13 as is, so just keep it around to play around with and enjoy. A lot of us can't even afford to run two vehicles, so consider yourself lucky.
