Just to add to Stan's advice, If you can afford it go directly to the manufacturer and have them fit you for your suit. No two people have the same body shape even if your heigth and weight are the same.
When I ordered my SFI-20 suit fifteen years ago, I went to Deist's shop to have them fit me.
Unfortunatley for me, and being 6'3" and 240, I didn't think about or explain to the seamstress that when belted in my race car, I sit low with my long (glamorous) legs cramped into a ugly geometric puzzle.
When I recieved the suit I tryed it on and proudly struted around the house......... every thing A-OK.
WRONG! When they straped my in at Speedweek, I realized my future might be best served as volunteering to be a High Soprano for the Vienna Boys Choir.
Luckly, Deist was able to split the outside leg seams and add two inches from ankle on up and make my drive a little more comfortable (if one considers comfort to being tightly restrained in a small closet, unable to move in any direction, with very little if any periferal vision, sweating like a slave in the cotton fields, and with enough adrenalin flowing to rotate the earth).
One more thing I did, was not only have my name embroidered on the front pocket area (if there was one) and right below it listing my Blood Type. Bob