Is it safe to unplug and cap off the vacuum line on the wastegate? I know a guy that did it and his truck built up boost a lot faster.

 

the only thing unsafe about plugging it the turbo will just keep on building boost until you let off the fuel or the turbo blows apart. a lot of people plug the line off.

 

Yes you can. And depending on the condition of your wastegate it will build more boost. Keep in mind anything more then 25-27 psi on the stock turbo is nothing more then superheated air and is doing you no good.

With stock injectors your not going to have an issue... And even with the wastegate unplugged it will still open once enough pressure is built to overcome the spring in the WG canister.