straight answer from APS 2.5" TD exhaust owner (my opinion only) :
if you :
_ want to stay N/A for a long time > go with single or TD 2.25" (because u will lose power in low end with TD 2.5" , although i gain 17 WHP from my APS alone but slow acceleration )
_ like the stock Z sound > go with single (nismo+HFC=beautiful original loud enough sound) ,APS sound beautiful very unique and loud with HFC (Little drone in 2-3k in RPM but i like it , and RASP at first acceleration then it gone ) over all i love the sound .
_ going to do most or all the N/A mod`s (CAI, spacer, pulleys, cam`s, headers, gears ..etc ) go APS 2.5" , you`ll gain back what you lost low end and the high gain of TD 2.5" . (i don`t think 17WHP gain is something negligible)
_ going FI >>>>>> APS all the way ,i didn`t hear or read any thing but good stuff about this exhaust and how he can handle a high pressure .

if you ask me if i want to change what will i go with 1) nismo+HFC take my chances with the crakes. 2) bassani or Turbo XS no HFC or TP .
i hope this will help , again its just me

 

yes finally a striaght answer and ty lol so even thow aps states that you will get low to mid rang tq, you really dont feel it and it actaully feels slower and the bassani would be a better choice because of the pipe size and x pipe. and the nismo+hfc i would go with but dont realy want to deal with the cracking issue if it would a raise and does that combo give you any feel on the butt dyno?? jw

 

wait for the motordyne exhaust to come out!!!

 

aps states > i don`t know about that but from my experience its more like med to high b/c the car has become faster to reach top speed but its slower in the first seconds and i`v lost the sound at first but after few weeks i gained back some, they told me the ECU needs few days to relearn the bolts-on mod`s and its not a good thing to do tune after every mod you do so just give it some time (and i find it very true i gained back some Trq but a tune after all air flow mod`s would be the best to do ).
for me as i said i like the nismo+HFC and i like the bassani alone, i`m waiting for a good video and dayno for bassani+HFC to see the least RASP comb before i decide of going back to 2.25" TD or single

turborevdboy11 :
+1 > wait for the motordyne exhaust to come out!!! also the results of the tests that they are doing on the xyz pipe and all