I need to replace the front piece of my ground effects. I've been debating on a couple at RK Sport and they both say they require the longer air spoiler up front to help air flow.

I'm a little concerned because my driveway is one big slope. Is this piece REALLY required and if so, can someone say how much further it hangs down over the stock one?

My stock one doesn't rub if I go slow, but I'm curious about this other one.

 

Short answer: Yes you need it!
Most who have NOT used the larger air dam have had problems. It sticks down a couple of more inches, and will most likely scrape.
Those of us who have the larger air dam for some time have had to replace them, due to all the scraping and bending, causing cracks and even breakage.

 

I put the ground effects on my car without the extended air dam and the car started overheating...even on the highway in near-freezing temperatures. Fabricated my own air dam extension and haven't overheated since.

 

Point taken, thanks!

Looks like I need to think about what I really want to do. Thought about getting the factory GM one again, but it breaks if you look at it wrong