I had the Greddy SP on my GS-R and after 3 years on my car all of the packing came out of the exhaust. Greddy would not honor the warranty because it expired. I was like damn this POS just lasted enough to get through the warranty. I dont have money to replace an exhaust every three years so I looked else where. I purchased the Apexi WS and had it on my car for 4 years and have no problem whatsoever. Now with the SP2 out it might be a better piece. Also you need to decide if sound is an issue for you because like Bryan M said the Skunk 2 is loud thats why I chose the WS because its on the quiet side being slightly louder than stock. GS-Rs rev high and at 80 mph the rpms are at 4000 and with a loud exhaust that can be VERY annoying.