Originally Posted by A-A-ron

Already have HFC's and a Cat-back.

Getting my Stillen Gen 3's delivered today.

I already know I'm getting a tune, but unfortunately the two reputable shops near me won't have weekend availability for about 3 weeks.

My inner car-guy reeeeeally wants to put them on ASAP.

Would it be a wise decision to not install them until the day of getting tuned, or should I be alright driving around for a couple weeks so long as I don't go full hoonigan?

Thanks!