So far I have had very good luck/results with the DSP. I first installed the 87 Octane tune right after I had installed a
Borla Cat-back Exhaust. Ran a lot better and by the seat of the pants seemed to have more power that was a lot smoother through the Torque curve. I recently installed the Steeda CAI, removed the emissions Catalyst in the intake right after the MAF with the appropriate tune from DSP for tha CAI. Noticed a bit more power, filled up with 93 Octane (can use 91 as well) and after running it a bit, went out on my favorite stretch of Interstate, exited and got back on. Started from a dead stop and did a WOT onto the Interstate again (about 1/3+ mile to merge), was hitting 115+, merged into traffic (had to slow down fast to 80), punched it to go around a 350Z, hit 115-120+ again rather quickly and was gone! I had previously done the same run right after the
Borla's were installed and only got up to 106-7, and 109-110 with the DSP 87 Oct tune. So now with the CAI, re-tune and 93 Oct, I am pretty satisfied in my investment. I will soon be adding the Steeda Charge Motion Control Valve Plates and the tune for them with the CAI. We shall see.....
My dealer's Service Advisor (Josh is a real Mustang guy) recommended the DSP over the SCT Xc (Not knocking the SCT), but I have had very good results with the DSP. So, take my results and compare them to others out there. One thing to consider, SCT is about to come out with the SCT II that is similar to the DSP, but DSP is upping the anti with some revised tunes due out in a week or so according to DSP. There's a thread from Nick at DSP on this here somewhere. So for my money (and I have spent a few thousand so far! lol) I am pleased with all my mods, especially the DSP Tunes!