Well, u have the basics in mind, x-acto and razor saw.
But you might also want:
1. a level building surface,
2. something to protect your plans (wax paper works fine),
3. good lighting,
4. plenty of thin and medium CA,
5. plenty of 5min, 15 min, and 30 min epoxy,
6. rulers (mm, cm, in ft)
7. list of things you want to change i.e. push rods, engine mount, wheel, ext.
8. a digital camera so we can see your progress,
9. a shape pencil,
10. and patients

Good luck, have fun, and keep us posted!
Ron