Hi-
Congrats on your new 3, and welcome to the forum!(yippy)
Take a look at your window sticker or at your registration for this info. Either will be a great car to drive and enjoy for at least as long as you are making payments on it. The "S" and the "i" differ in the wheel size and a bit of displacement engine wise. Not a huge difference between the 2.0L "i" engine and the 2.3L "S" motor. I seem to recall less than 12 hp between the two. Both motors are super peppy and very reliable. There are also tons of performance upgrades available for both if thats your thing. The Speed3 is based on the car you now proudly own, so be confident that what you drive is absolutely rock solid and a blast to drive.
Have a blast with it! Zoom Zoom(drive2)