I was undecided between the 335i and 335is. The is has N54 320hp/332tq and short overboost of 370tq, 7 speed DCT. I'm a paraplegic so I figure I wouldn't be using the paddle shifters much so I opted for the 335i, M-Sport Pkg, 19" 230 wheels, NAV, Conv Pkg, Prem Pkg, Heated Seats and I love it. Just last week, a year after I bought it I added the BMW PE ($1,124)and PPK ($450) + installation cost ($420). I'm very happy with the new sound and added performance.
Of course there are aftermarket performance tunes with more hp/tq than the PPK but my plan is to keep her 6yrs/100k miles or longer.
Both are great cars and it all comes down to which one you want. I saved about $5000 by getting the 335i. Just spent $2000 in the exhaust and PPK.
2016 BMW M4 Convertible(F83).
2011 BMW 335i/E93: M-Sport(Sold)
2007 Dodge Charger SRT8 "SuperBee"
2012 Dodge Charger SRT8 (Wife's Car)