There have been some surgery horror stories. The penis is a very complex biological mechanism, not a race car that you can take apart and rebuild faster and better.
You're already pretty huge if those are accurate measurements. The girth is much thicker than average, and is what a lot of people consider "perfect," if they were allowed to choose a partner by penis girth alone.
Seriously, I'm thick enough, but like you, wish I was longer. (Even though nobody else has ever complained!) But nobody will be putting a knife anywhere near my cock--the scarring, the risk that it won't work right afterward (hardness, sensitivity, won't stand up when erect), the pain, the healing and aftercare... No way! (I like my cock and the pleasures it leads to too much to risk.)
One thing that might help: if you want to turn a grower into a shower, do some jelqs every day.
My own half-hearted PE effort over the past 5 years (no routine at all) hasn't made my erect size much bigger that I can tell, but do I have a much better flaccid "hang" than before I started, and that makes me like own penis all the more.
You don't need surgery. Leave that for the unlucky guys with 3 inches hard.