The low turbo boost code is likely related to a split in one of the 2 factory turbo hoses that run from the turbo to the intercooler and from there back to the engine. Take both hoses off and carefully inspect them particularly on the under side. Splits can be small and hard to see or very large and obvious. The fix for both is to install Samco hoses (
http://www.boostcontroller.com/index.php?category=328) allthough I understand there is an improved factory hose for the turbo to intercooler side. There is lot's of chat on the this forum regarding this issue that you can find with the search function. See for example
viewtopic.php?f=5&t=60050&p=666863#p666863.
I cannot say for sure, others may know, but I suspect if you get the GDE tune and have someone like Autozone clear the EGR CEL that you won't get that CEL code anymore without doing the referenced fix as the usual failure mode for the EGR is closed.
By the way when you have the turbo hoses off that a close look at the air intake hose from your air cleaner to the turbo. That hose has a nasty habit of decaying, also from oil, and falling apart down just before the engine end right near where the hose from the "hockey puck" on top of the engine "Ts" into the air intake hose. A replacement is available on line or from a dealer. It's not very pricey and the dealer price shouldn't be much more than online when you factor in shipping.