GTi-R block (in particular, the sump) is different. The sump is longer and wider on FWD. It's hard enough getting clearence (and driveline angles correct) with RWD yet alone the troubles you'd have with the FWD block. The head is also different, both to the RWD and non GTi-R FWD's. And as has been said, dizzy is at rear, water routing different, alternator is opposite to RWD and too close to run a RWD Turbo as there's fook all room for pipe work. GTi-R turbo is turned around.
Not saying it's not possible, NA FWD SR20 in RWD set up has been done. But there's a LOT of customising involed and if you cannot do it all yourself, paying others to do it is not worth the time, money or effort as opposed to using a RWD.
And you say you want to use GTi-R quad plenum to be different, more power? Again, not worth the time or effort as a simple bolt on or ECU mod will net same gains. My 2c.