I just broke in my WRX and was looking for a good first mod. If I got a K&N drop-in, what kind of difference would I get? What about an up-pipe? I read somewhere that up-pipes without the flex section will eventually break, which would, obviously, suck. I think I read this at some manufacturer's website, so it could just be bias speaking.

I can't really decide what to do, and was just looking for some good insight.

 

Remove the intake silencer FREE*
Downpipe $400.00
Up-pipe $200.00
Intake $200.00

Those are all good mods. Id say go for the Upipe and Downpipe and install at the same time. I got both installed for $150.00.

 

I would hold off on the intake for now.. It can easily throw off the MAF readings and make your engine run/idle less than nominaly. I've been through it before, and ended up taking off my intake. The stock airbox works great, and is not really a restriction on the small stock turbo. I do use an higher flow K&N panel filter though.

My first mods(i don't have many) that seem to work great on my car were.

1. Catless turboback exhuast(2.5inch Stromung downpipe +fabricated the rest+ universal high flow muffler(saved alot of money vs. buying an $500 catback that does the same thing)
2. Samco IC hoses
3. GFB MBC(not the best way to control boost, but if used conservativly it does work great.
4. GFB pulleys
And then I went into some more mods that arn't as cost effective like a clutch upgrade(cause my stock one went at 30k miles), and lightweight flywheel etc.

1-4 are all great begginer mods though, but you could prob. get the same performance now by just getting an ECUTEK flash

 

http://www.turboxs.com/
more goodies to look at