when you get to MFN just park where your told to, isnt a stand or anything.
https://www.google.co.uk/maps/dir/53.0021541,-1.2820182/MFN,+Shipley+Gate,+Eastwood,+Nottingham+NG16+3JE/@53.0131301,-1.3198716,4398m/data=!3m1!1e3!4m14!4m13!1m5!3m4!1m2!1d-1.3029526!2d53.0168826!3s0x4879eb600c68b51b:0xabba9aa9142d365d!1m5!1m1!1s0x4879ec844553bb61:0x176becb45ba0f72e!2m2!1d-1.3132529!2d53.0029644!3e0?hl=en
Hawk box will be fine. I ran one at 400/420 for 18 months no bother. They are about the strongest 5 speed you can get. I'm or sure if the hatch uses the same box or not.
TBH just get it done by subaru. yes you can get it done else where as long as its a proper garage, check the warranty t's and c's though, usualy somethign in it about has to be serviced at a vat registered garage or summit like that