So I recently picked up a IX MR that was tuned in Denver CO(~5,280' above sea level) I live in SLC Utah(~4,200' above sea level) and I feel like I keep running into issues. Surge, Idle sucks etc. etc.

The car has the following mods(had them when it was tuned as far as i know)
Injen UICP and LICP
Injen Intake
COBB BPV (100% Recirc)
Greddy TI-C Catback
And the factory BCS was replaced with an Ingersoll Rand 3 port BCS. From looking at the steup only 2 ports are used on the BCS one port to the compressor side of the turbo and one port goes to the WG actuator.

The car Idles like it has cams(stock as far as I know) It realy hunts around, and it sounds like it misses every 5-6 seconds when idleing, its almost as if for a split second it cuts out. Part throttle cruise sucks, when pressing the throttle(like when in stop 'n go traffic) it feels like nothing..nothing.. nothing... then bam it finally starts to move(all in vacuum, im not talking about spooling) Also Im having surging issues(WG?BPV?Compressor?), Its hard to tell exactly what the problem is, but it happens part throttle building 8-15lbs of boost, If I give it more throttle it gets worse, If i back out it stops. Full throttle it doesnt seem to have an issue.

My question is, Would the altitude changes cause these issues? Are there things I could check?(BPV Spring adjustment? Boost leak test?BCS hooked up correctly?)Or does it just sound like the tune it has SUCKS?

I'd like to get a TBE and a Wideband and have it retuned, But in the meantime I'd like to make sure Im not causing any issues.
I've got a 1.3u cable on the way

Thanks for any help.