l have a 1999 subaru impreza 2.5rs and l wanna do this engine swap because my engine has a ton of miles on it and l hear its better than doing an sti swap

yeap, a lot of work

Yes it will fit. But not nicely. The steering column is on the wrong side of the car for it to fit easily. there are ''subaru owner club'' forums with much more detailed about this.

It has been done by a couple people but l do not think it is worth all the work. There is not much aftermarket support for it and better engines can be had for the same amount of money. Turbo is these day is spool so quick and are so efficient that two small turbo is do not really have any advantage over a bigger single unit. If you just want it for the rarity, it could be cool but that is where the project would end.