Currently in a 2008 STi. Been lurking on here for a while now. Will bite the bullet eventually, but it'll probably be a 2017. Might even hold out for a GT350.
I had a similar experience with my test drive (GTPP 6MT - Sport mode). I currently drive a modded STi (~350hp) and the Mustang felt a bit sluggish to me in comparison. But I know the feeling can be improved with a tune, some suspension work, an exhaust and a new shifter/bracket. I still plan to...
Congrats on the new Mustang, but a modded MS3 isn't going to hang with a GT.
I say this as someone who owns a modded STi, which is faster than a modded MS3.
Haven't seen this anywhere. I've mainly seen praise for the Roush Stage 2 & 3.
And don't forget, you're just a pulley and tune away from a bit more power if needed.