Best is finite term, & most of us aren't in a position to compare different mfg.'s offerings.
H-pipes are favored for sound.
give you 1 or 2 extra hp over an H.
My tuner recommended Kooks when I had work done on my 11
. Went with 1 3/4", catted X pipe, stock mufflers. ( N.J. is an inspection state )
Went with Kooks on my 14
also, 1 7/8", " green " catted X pipe, stock mufflers.
Both of my cars run custom tunes by:
Mustang & Raptor Performance Parts & Tuning-JDM Engineering
My tuner sells " canned " tunes, but it's not the way I chose to go.
I'm sure others will chime in with their opinions......good luck !!