I'm not sure without seeing the actual dimensions, but I doubt you have room for the proper size aero's with 3-18's. Even though it may not be the most cost effective for you, changing to 18's with the proper coil configuration would probably be best to maximize the Stetsom.....or even go with the 15's. Take my opinion with a grain of salt though as I'm inexperienced with wall builds. I could be completely wrong in my thought process Hope it works out for you regardless of what your decision may be. I'll be watching your progress with the build