While youve taken off the main restriction on your exhaust, you are still hindering flow with the stock setup. It may or may not hurt to wait, and while I agree with holding off until you have more mods to get the best bang for your $, throwing on a free flow exhaust might be an issue. As exhaust gases expel at a faster rate the turbo is allowed to pressurize your system faster leading to a boost spike, and your ECM cannot enable proper fail-safes (boost cut/timing/fuel)...this is why throwing on a testpipe with no tune is dangerous. Realistically its not going to be a big deal but your going to notice faster spool times and a better higher rpm band. Hell, your planning on getting It anyways so why not just throw it on and see if causes issues, taking it easy until you know its safe.

 

get a down pipe and exhaust then retune. that way you will have all the piping before you retune

 

I would just gather some of the top mods I would want and then wait to put em all on and retune, cha ching.

 

What are your current mods???? I would wait til you get all you need for the TBE and whatever other mods you want to put in before you tune. I got tuned and now im looking at putting in a biggier intercooler, injectors and fuel pump. Might as well do everything at once so you dont have to keep paying for another tune!