Are you sure an M.D. is removing it and not a MBChB/MBBS or D.O.?
Kidding aside, lap procedures have very little downtime. I've observed a bunch of laparoscopic appendectomies and I think the downtime would be similar, i.e. you can jog home from the surgery.
Just kidding.
They can go wrong, but only a small percentage do. I would recommend you research your Dr. for insurance claims against him, to see what prior mistakes he might have had to pay out for, and make sure he is holding good malpractice coverage.
If all goes well you'll feel like going home that night. And no, there should be no impact to the rest of your digestive system afterwards.
Oh please, doctors don't know anything about insurance. They hire people to take care of that for them. Ask any doctor you have about insurance and they'll have you discuss it with their staff. They don't have time to talk about insurance.
On topic,
Xopher, you should probably get a second opinion. I was having pain in the area of my gallbladder and had some ultrasound and CT scans. Nothing was obvious. I got a HIDA scan and they said I have a non-functioning gallbladder and they wanted to take it out. I asked them what would happen if I didn't get it taken out. They explained that I could leave it there and would have to deal with the pain.
I lost some weight and I haven't had any more pain there.
[edit] At Memorial Hermann here in Houston I had some Lithotripsy done on a 6mm kidney stone. I went to the hospital the day before the procedure to do some blood tests, fill out paperwork, get my vitals taken, answer questions, and take care of the billing information. Most hospitals will allow payment plans if you are unable to pay. You will likely meet with a person who is skilled at pushing you to pay as much as you can. Memorial Hermann wanted to know how much I could pay now, and said I would be expecting a phone call from payment services to set up a payment plan.