R3tr0grade

Hi, I am running the stock twins on my car and have been chasing an intermittent noise that happens when my primary enters boost. Its very hard to replicate but my girlfriend and I call it "the honk". It seems to happen more on the highway at very light load around 2800ish but it doesn't always occur.

Either way I have smoke tested and have no boost leaks when the engine is cold. Replaced CRV, ABV and loose intake hoses. Replaced y-pipe coupler which was leaking. I have also tightened the bolts/studs connecting the turbo+manifold to spec. I have tightened the turbo heat shields.

Separate from the turbos I have also tried unplugging the air pump to see if it was the "moo" and replaced my motor mounts. The latter was needed anyways as I still had the stock aluminum arm on the driver's side.

Yesterday I hooked up a boost gauge to see what my pattern is and its mostly in spec but I'm getting a spike to around 14/15psi at transition that dips back down to 10psi almost immediately. Also worth noting that the noise on the primary did occur once during the drive when entering boost but PSI seemed to be at the expected level for that RPM (climbing to 10PSI).

Mods are:
- HKS downpipe
- HKS hi-power catback
- ARC intake

Are there any other specific solenoids, check valves etc that I can test or look at replacing related to these symptoms? I've read a number of posts about how many mods are acceptable on the stock ECU/fuel system and I thought I was still safe. Other than these issues my car runs great. Thanks in advance.