Welcome! And sorry to hear about your other ride... I'm sure that was very frustrating for you. It sounds like you have some pretty good plans for your WRX though.
- Look for a downpipe with a bellmouth design (catted or catless is up to you)
- Definitely look into engine management (Cobb AP, opensource, or a pro-tune) at the same time you upgrade your downpipe
- A catless uppipe is a great idea for your car and they're all similarly sized (try to find one with a flex section for easier fitment)
- A turbo timer isn't really necessary on a stock turbo since they're air, oil, AND water cooled... right now it's more of a bling factor for you, so that's ok
- An atmospheric-venting BOV (the kind that sounds cool) is somewhat of a touchy subject around here. From everything I've read about them, I would avoid upgrading yours until you upgrade your turbo and it becomes a necessity. Venting to the atmosphere on a stock WRX causes a rich condition between shifts and can cause damage.
07 WRX (Albins 5MT + Blouch 20G)
Jorge Carrillo Tuned (365 whp/340 wtq)