Boost issue.. Kinda...

[2JZEFINI-17]

Ok so I wanted to see how my car boosts through the first 3 gears since I never really tried going WOT through the first 3 gears. Well first gear went to 10psi, 2nd gear went to 5 psi, and 3rd gear went to 5 psi. Shouldnt it be 10, 10, 10?? Should it hold steady boost readings or drop a little? I think my car is fairly quick but I am sure that if I can do 10,10,10 it will fly. Do you guys think this is a boost leak issue somewhere in the system? How much does it cost to shim the wastegate and can it be done easily? I heard that shimming the wastegate lets the turbo spool to 14 psi. I also heard that a divorced downpipe gives the supra 30whp is this true? Sounds like a rediculous gain for one upgrade.

I know this is alot to read but my last question is what kind of power am I looking at with these upgrades. Just give me a rough estimate. I was thinking like 320hp?
Aluminum Radiator
Front mount intercooler
intake
divorced downpipe
test pipe
shimmed wastegate
14 psi
2 1/2 in magnaflow catback
HKS SS Blowoff valve
By the way I have a new HG, Timing chain, and ARP headbolts.
Would that setup be safe if I used 14psi only when racing and kept it at 6psi when daily driving?