If your vehicle does not come with the puddle lights originally then it is not plug and play. You will have to replace the mirror assembly with a puddle lamp mirror. And even then it may require playing with the wiring.
Just like everyone is saying. You can reuse the brake lines. Just need pin kit and crush washers.
https://www.opmustang.com/store/p160/2015-2019_Mustang_GT_Performance_Pack_Front_Brake_Hardware_Kit.html#/
YES! your non PP vehicle will be a direct bolt on. Chef jpd meant to say "non PP GT" and not "Base GT". I have a premium non PP vehicle and it its a direct bolt on.
I did the Brembo upgrade for the front with the Z26 pads. Left the rear stock pads in place since there is no difference in rear brakes between non PP and PP cars. No issues with brake dust. I'll replace the rears with Z26 pads once they wear out. But that will probably be awhile.
So you replaced the 350R style splitter with an IKON splitter? What's that look like? I'm still running the GT/CS splitter but have thought about the 350R style. Both look good.but I'm ready for something different.