You got to have realistic goals, if you are serious about taking on a procedure like this. Definitely consult this with your doctor who will have more detailed information about this, and may recommend you to a board certified surgeon.
Mind you those procedures aren't cheap, and I definitely wouldn't dice my luck on whoever's practice is running cheaper. How old are you BTW?
Prostate surgery isn't the same as penile elongation, I'm sure you know this. Whilst both are procedures that separate tissue, penile elongation isn't nor doesn't remove malignant and cancerous cells. There are other further components that factor into erectile inadequacy, such as chemotherapy, cryotherapy, hormonal therapy, and/or radiation.
However I do agree with your assessment regarding going under the knife CAN cause problems. As the saying goes "If it ain't broken, don't fix it".
I've seen vids of the procedure before, and yes they do detach ligaments from the pubic bone, this is essentially how they are able to expose more of the penis. Although they didn't fully pull out, all that was hidden. I don't believe they chop anything, just reattach the ligaments to the pubic bone.