Looking for replacement windows do I need a Flange?

I am located in central fla and am currently looking for replacement windows for my 2 story home, block 1st floor stucco over ply 2nd story. I really like the PGT Spectraguard window but have heard both sides of the argument about whether the flangeless construction of this window is acceptable for the 2nd story installation. Can this window be sealed adequatley or do I need to use a window with a nail fin and the existing stucco removed and restored around the fin? Will the install in the 1st floor block construction be sound without a flange? Thanks for any feedback.

Either with or without fin can be done correctly.
Your local codes and the installer determine what is best.
The fin install will be the most expensive. You do not have to remove all the stucco , enough to get the fin in plus what ever type of finish trim that you choose to fill in with.
theWindowNerd....

O.K. so it really comes down to a quality installation? I can see where the non finned frame would be more attractive to an installer. My concern was the installer being able to properly seal the exterior gap that will be created due to no stuco overlap with the non fined or flanged frame. I addressed this with the installer and he mentioned that they also have a $12K blocking(trim?) cutter that not many in the industry have, he said there will be an alloy blocking installed after the window has been caulked. Not sure that helps with water intrusion, guess it is more of a finished look addition?

A method to use is to cut out the old window.
Retro fit a metal drip cap.
Flashing tape the perimeter.
Install finless window.
Apply closed cell W&D foam.
Finsh the exterior and apply high grade sealant.

Big +1

Solid details Anthony.

Thanks for the reply anthony, it helps to hear opinions of a professional that does not have an agenda in my purchase.

What type of framing do your existing windows have? Your description will help me give you a solid answer.

My home is a two story, masonry over block 1st floor and 2 x 4 framing with plywood sheathing with stucco top coat on the 2nd floor.