Impulse Responses through Gearbox

Is there a way I can send a DI guitar signal to audacity and then run a VST to apply an Impulse in Audacity?

Audacity is not a particularly good VST host application - it uses a third party plug-in (VST Bridge) to provide partial VST support. For doing VST stuff you would be better off with another program such as Reaper, Cubase, Krystal, Sonar, Reason, Nuendo…

Alright. i still don’t know if I can send a DI signal from an application like Gearbox standalone, but does the partial VST just work slow and maybe I could record then apply effects later or does it just work like crap?

Audacity does not do “real time” processing, it is purely for working on recorded files, not live audio streams.
VST support only works with some VST effects. VSTi (VST instruments) are not supported.
All VST effect have only a basic interface, the fancy graphical interfaces that are common with VST effects are not supported.

When Audacity works with a particular VST effect, it works fine, though it may be more difficult to use because of the basic interface. When it doesn’t work with a VST plug-in, it doesn’t work.