impreza 2.5ts swap option

Hi everyone , my first post here :)
I just got a impreza 2.5ts 2003 for winter driving basically
The car drive well but i miss the ummmph of a turbo engine.
I would like to do a swap .i have access to a garage and it wont be a issue .the only thing is im lost in all those version.
I called a swap jdm garage who told me to take a version 5 6 or 7 but everywhere im looking they are too expensive
Im looking at a version 3 ej20t wrx
From what i read its 280 hp right ?
Also if i take everything like motor tranny ecu wiring i would be fine with a v3 ?
One last question will the stock exhaust will fit for a while ? ( i should have the proper downpipe with the engine)

Thanks for your help i cant find specific answer :)