So i just installed the Stillen front splitter on my 2008 350 and tried to put my aluminum undertray back on and it didn't fit. It wasn't really that close either. The splitter fits and looks perfect, but the front part of the undertray just won't reach, is there something I'm missing?

 

Well, which undertray do you have, and which bumper?

 

I had no problems running the TBW undertray on mine. 03 bumper with Stillen splitter

 

Zspeed under tray and stock 08 front bumper

 

Sorry, but I just can't understand what you're talking about, as those pieces should all fit together well. Can you post a picture?