Forgive me if this is covered in another thread, I've tried searching and get some answers but my main questions still remain. My main question is what is the size difference, (if any), between an Air-Knit and an Ultrafil of the same "size". I fit perfectly, (tight but loose enough to move around and look good), in an Air-Knit 54. Would an Ultrafil size 54 be slightly tighter? Would it be looser? etc. Or is it the same and I don't have to go up or down in size? My secondary question what is the difference between the two? Ultrafil LOOKS, (have never held one), like it's smoother and tighter... and I imagined, (I'm sure incorrectly), it'd be like an Edge 1.0 vs 2.0. Could anyone please elaborate on these? Thanks a lot guys.