I've heard plenty of guys talk about gel v. injections, and from what I've heard they pretty much do exactly the same things to you. Your voice will deepen, you'll get hairy (you won't grow a beard right away though. Sorry.

), you'll get acne, your body fat will redistribute, etc.
Ultimately, your changes will vary from other guys' changes because of how your body reacts to the T. Maybe the changes will take long, or maybe they'll happen quickly. There's no way of knowing until you start T yourself. Good luck.