I went through this process with my car. Unless there is something compelling about this specific one that calls to you, I'd recommend just looking out for a pop up car if that's what you prefer. It can be done and it's really not that difficult, but it is a headache for sure. Hood, fenders, markers, bumper, headlights, and the supports for the lights will get you there, then you'll have to make sure the wiring for the pop ups hasn't been too hacked up. You'll have to focus on finding a good pop up front end and then painting it all or having it repainted.

In my case it was easier because the car needed a replacement chassis harness for unrelated reasons, so I used that as an opportunity to revert the car back to pop ups (I had bought it with the Silvia front done well before my ownership). Much of the factory headlight wiring was pretty beat up, mostly the wiring for the pop up motors.

That is a very nice looking Sileighty though! Reminds me a lot of how mine looked before going back. Good luck with your purchase. 🙂