spend 5-6 grand on a new ej25 setup. Even an oem shortblock from subaru will work fine and you have good flowing heads. get them checked. Then youll knock out your upcoming maintenance of waterpump/timing belt ect. youll be flushing the coolant. Replace with a almost stock clutch (to keep from blowing up your trans). maybe a VF39 and a tune. front mount can be had for like 500 bucks off ebay (they work fine) and can add a good amount of power over a top mount if tuned properly.
Dont waste money on a 3 port ebcs, header, intake, intake inlet, stuff like that. OEM is all just fine.
Thats what id do if i have a 95k mile 2 liter wrx and 5-10 grand. I make it a zero mile 2.5liter Hybrid on the Conservative side.