i dont know if id say that. most performance parts (mods) are much higher quality then oem. you get what you pay for though. cheap parts = unreliable.
certain year subarus had alot of problems with head gaskets. i THINK it was 2002-2008 models (around those years). theyve also had alot of problems with there automatic transmissions (some models).
i was about to buy a 2001 audi a4 quattro 1.8t 5-speed. its an awesome car for winter/summer driving. unfortunately i broke my hand and had to have surgery and ive been off work for over 3 months and had to support myself with my car money

. there not super reliable but if you stay on top of maintenance and can do repairs yourself there not much more expensive then your average car.