Sorry bro that I'm just seeing this. We were actually the first to start running splitters on the 09-14 fronts. No one manufactured one at the time so we came out with our own.
Anyways, for install, we 100% always recommend mating it with the Zspeed aluminum undertray. Reason for this is to add additional support and mounting locations. There are very few mounting locations under the z from the oil pan all the way to the front of the bottom of the bumper/valence.
For most support, but the rear side of the splitter to fit around the the zspeed vent, and the rest will be above the zspeed.
Under the bumper we started back in 2011 by using plastic washer, 1/2" in the 2 centers, and 3/8" on teh outters which you can shave down to an angle to fit the curve perfect. THIS we actually found functional which helped pull air creating a duct inlet straight to your oil cooler or radiator. Win win right?
We have been using our NLTA splitter now for 6 years, still on the first one and its lived up to the abuse.
Please DM me directly or reach out anytime with any questions you guys may have. We support both our splitter as well as APR's. APR's is a big more aggressive then ours.
