Replaced (with OEM stuff) the factory front spoilers (all 3: the little ones in front of the wheels and the big one on the lower front edge of the bumper). They've gotten pretty torn up over the past couple of years, to the point where I think their aerodynamics are compromised.
I had been putting off replacing the main one because I didn't want to deal with the riveting. Turns out the new OEM replacements come with bolts instead (don't ask me why they ever put rivets on what's clearly a wear item). Just had to cut off the rivets on the old piece and then enlarge the holes in the bumper very slightly (1/4 inch drill bit).
Also, I installed Z-speed's aluminum under-tray. I had been wanting one forever, but I knew my old 1-inch oil pan spacer wouldn't fit under it. Figured I'd give it a shot with the new AM Performance oil pan.
The good results:
- It fits the oil pan fine (the drain bolt just barely touches the undercover)
- It looks like it would give better cooling to the pan (and seemed to during one test drive today vs normal behavior)
- Probably better front underside aero, but who knows without testing
- Seems stronger against possible underside damage.
The so-so results:
- The Al is thick enough that this mod actually adds roughly 2.5 lbs to the front of the car vs the non-Nismo plastic undercover. All things considered I'm ok with that tradeoff, especially being so down low and spread out wide.
- Z-speed and Z1 both warn about incompatibility with extended oil pans, but I found a new incompatibility: Hotchkis front sway bars. The Hotchkis bushings stick out about 1/8" (maybe less) more than the pan technically allows for, and then on top of that they have grease fitting nipples on the bottom that really get in the way. I worked around the grease fittings by cutting holes in the undertray with a 1-inch hole saw to let them peep through, and then the tray just barely stretches over the bushings themselves and bolts on securely. It's a little scary having those grease nipples sticking out, they're gonna get killed if I ever bottom out the front of the car. But on the other hand they're just grease fittings for swaybar bushings, it's not a catastrophic problem if that happens.
- With the AM Performance oil pan Z-speed's little oil change door is useless, and one of the two bolts for it hits the pan to boot. I just removed the offending door bolt for now, and later I'm going to remove the other and weld the door shut so it can't rattle. I'm pretty used to removing the whole tray for oil changes anyways.
I expected all of these sorts of issues given how many unusual mods my car has, so the fact that it's on the car and usable was a good overall result for me, just things to keep in mind for others.