OHHH I know how you feel!!! I just started mine last week, it went for it's first test drive yesterday!!! I'm still smiling!! LOL
Grand Prix GT Top Swap XP Startup - YouTube
Yeah, I don't think there are any tuning specifics for the HV3 so removing it will not be an issue!! Also, pretty down pipe or not, it's a down pipe with the u-bend deleted out, take a pic of it and throw it and the HV3 in the for sale area see if you get any bites. Sure someone wants it!!!