I looked for any DIY threads similar to what I did and could not find any. Since I decided to tune my Denali going with EFI from MJ Engineering which I ordered yesterday. I did my DIY intake mod which really woke up my engine. Using K&N drop-in airfilter which I have had in since 2008. I can only imagine how well it will run once I get the EFI AutoCal tuning. I did this mod to my Dmax in 2008, it worked very good and the gains was similar to others that had Banks RamAir and S&B CAI intakes. The Intake Ambient Temps dropped 20-25 degrees and the MAF g/s @ idle went from 26-28 to 40-42, using aFe ProGuard 7 drop-in airfilter. Monitoring PID's using the Edge Insight on my Dmax. The nice thing about doing this compared to buying a CAI you don't have to worry about MAF location issues. Cost about $45-$50 for the K&N and about 2 hours labor.