greatest thing since sliced bread. Only costs ya $0.50 cents. (unless you go for the high-grade performance washers...which I think are $1).
Slap them in the bolts of the exhaust back where your axlebacks connect, and wallah! Instant noise!
I did this for awhile (no joke)...it actually does a decent job for as much as we poke fun at it. Lots of posts about it (I know I had a few about it).
2008 G8 GT #509 of 888 - Ignition Orange
Performance: Kooks 1-7/8 LT's, Solo HFC & Mach Shorty, NEP OTR Intake, NEP Dyno Tune, VMS HSRK, Ported TB, Widened Stock 19" Wheels w/ 285's
Appearance: 5000K HIDs, NEP Gauge Bezel, Auto-dimming Mirror, third_shift studios 888 Shifter Plaque, GXP Front Fascia & Diffuser, 3.5" Exhaust Tips
349 RWHP / 366 RWTQ
Best 1/4 - 13.215 @ 105.17MPH, 60' - 2.01 - Prior to headers...new time coming (hopefully)