Manofsteelpt

Hey guys... I'm getting ready to buy a tune for my 09 CLS63, and I'm wondering what kind of performance can I realistically expect? If I end up with 20-25 HP and 20 or so Tq, will it be noticeable to me, or just during timed events? Will my 0-60 and 1/4 times go down .1-.2 secs?
Thanks