Newbie help, car not running right

Hello my name is lee and I just recently bought a 2005 lgt 5mt. I'm not new to subarus but I'm new to turbo cars... Well it's a stage 2 with cai, up and down pipe, and full exhaust, tuned for 20 psi by shamar from infamous in so cal via open source. This is what happened, bought the car, previous owner swapped back to stock intake to visually pass smog, cai filter was dirty so I waited for two weeks then got a replacement, car ran waaaay better for about three days then started to hesitate while accerlerating then it went into limp mode, and yes i did tons of research on here. I panicked and swapped back to the stock intake and unplugged the negative. Car drove a lot better but drove a lot weaker and boost is now only hitting 15-17psi and doesn't have the punch like how it used to. I changed the spark plugs to Ngk xs checked all the vacuum lines and the tee connector, all good. Can anyone help me out, the car drives fine but it's driving me crazy!!!! Does taking off the negative mess up the tune??? It was raining for the two days that I installed the cai and happened the third day.... Any help would be appreciated. Thanks

And I do have a small exhaust leak on the up pipe in the flex area but it was leaking when I bought the car

You have to run the intake that the car was tuned on. You can not switch back and forth.

 

On a side note, get rid of the tune by Shamar, there is tons of threads that talk about how his tunes were garbage.

Really? A retune should fix the issue then? More than likely? And how safe it it to keep driving with the mods and bad tune? Thanks for the quick reply

I'd suggest doing a boost leak test. Does the car still have the oem tmic? If so, they're known to leak above stock boost levels. And as Brian said put the cai back on if it was tuned for it and you probably should get a retune just in case. While you're at it you could also clean the maf.