Most middle to high end tx have settings and option that allows you to tone down the servo speed. I know the MT-4 has this feature and cost about $250

EXP does not necessarily slows down the speed. Instead it just expand or limit its aggressiveness.


EDIT: if your on a budget, you can pick up the flysky gt3b for under $50 and has a ton of features.
http://www.hobbypartz.com/79p-gt3b-carradio-lcd.html