I checked out Marat's profile on atptennis.com and it says that Marat plays with Head i.Prestige but it doesn't specify which model. I believe there are 3 models but it doesn't say which of the 3 Marat plays with. Sorry i couldn't be of any more help.
Safin doesn't use i.Prestige. If You take a look at area where "V" of the racquet joins the oval, on i.Presige there are the grooves and PC 600 is complitely flat (Safin's racquet). Besides this, CAP grommets on his racquet go all the way down and square shaped at the end (like PC) while on i.Prestige grommets rounded at the ends and much shorter. Besides, his racket has plastic "thing" above the grip (only PC has it) and his but cup is brown/silver, from PC, not i.P (grey/black). Safin all the time played with PC 600 (even after signing with Dunlop, most of the time he was using painted PC which has unique feel). It is less stiff than i.P and give unbelivable feel for the ball. And size never been a mid+, only MID. He always played with stock racquet without any modifications (only this year added some lead tape), his grip is original Head leather, overgrip - Tourna (at least how it looked like when I've seen his racquet close a few times this year) but I can be wrong as few grips looks like it.