What modifications can be made to increase horsepower and/or torque?

I was going to run through a list of ideas, but then I found this site and thought it would be easier to let you read through the options yourself. http://auto.howstuffworks.com/question395.htm Good luck!

The first two things you need to do are the good old intake and exhaust route. Have a good mandrel bent exhaust system put on (I prefer the Flowmasters), buy a good cold air intake (K&N FIPK), and have your chip reflashed. This will cost you $700-$1000, but should probably yield about an additional 30 HP.

Cold Air Intake (CAI) and tune. If you really want to increase hp, buy a supercharger.

CAI, headers, cam kit, reflash comp. , ect.

yea man pretty much the simple things like everyone said, full exhaust, headers, intake, if you want you could upgrade ur tb but that might be a hassle. or if you want to be a badass get a rear mounted turbo.

Get a JLT intake and a Magnaflow exhuast. I got about 31 hp from the intake alone and a dyno tune. It cost me 500 for dyno tune and intake together. If ure looking for not only horsepower but also speed....get 3.73 gears or 4.10 gears. If you are planning to supercharge in the future get 3.73 gears and if not then get 4.10 gears. It will wind it up alot faster and make your mustang come alive...i've driven my mustang w/ stock gears and a stock mustang gt 07 with 3.73 gears and damn did it make a difference. It will cost about 600 with gears/install. I wouldn't mess with gears my self...but thats just me. Americanmuscle.com has good products or buy straight from ford racing.

I have a 2016 2.3L turbo Ford mustang and I must say the best addon I have found to date is a small unassuming piggyback device from a company called sawyertuning: http://www.sawyertuning.com/product/best-ford-mustang-2015-2018-st9pro-max-boost- stage-3-performance-chip-tuner-2-3l-ecoboost-engines-35-wheel-ft-lb/ Install took 20 minutes tops and I noticed immediate improvement in turbo lag once I fired her up. Am getting it dynoed soon and will have more permanent numbers then, but it definitely feels like an extra 10-15HP easily. I would suggest this because it works instantly and requires no programming whatsoever