Is Rib Removal Dangerous?

Rib removal is safe if performed by a board certified plastic surgeon. I would advise you to
schedule a consultation with a board certified plastic surgeon for a detailed
examination to discuss all possible treatment options and what your
expectations are. 

Rib removal is relatively safe in the right hands with experience in handling rib removal techniques. The procedure usually involves removing the 11th and 12th ribs which are the lowest ribs or floating ribs. Despite this risks are possible with the surgery as with any surgery.

Thanks for your question
Generally, the resection of ribs involves a long scar along the backside of the chest or upper waist. İ perform a minimally invasive approach to either limit the length of one incision per side or make 2 much smaller incisions. Smaller incisions result in smaller scar, less pain, and quicker recovery.
There are no long term side effects.
Best of Luck

... If performed by a certified surgeon. However, there aren't many surgeons out there willing to do it as a simple cosmetic surgery since it carries many potential risks.

While rib removal can be performed safely in the majority of patients having the procedure, it does have significant risks and is not  a procedure that most board certified plastic surgeons would be willing to perform as a cosmetic procedure.Robert Singer, MD FACSLa Jolla, California

The rib cage ends well above the level of the belly button so although removal of lower ribs may give you a more hourglass shape it will not in and of itself decrease your waist circumference or pant size. If the ribs are removed via a tummy tuck incision the final scar should be easy to hide under an undergarment. Since historically ribs have been harvested by plastic surgeons for bone grafts without long term problems at the donor site the procedure should be safe when performed properly in the proper patient.