Ive noticed over the past few thousand miles that the yo-yo is much more noticeable. If you're not familiar with the yo-yo....Im speaking of under accelleration the car feels like it surges and is no longer linear. I know Detroit tuned makes a better bypass and alta is working on one as well. Anyone use a product like this or have luck at the dealer level?

 

I had yo-yo with my 2003 MCS and when I got my GP I was happy that I did not notice the yo-yo. However, now that I have 15000 miles on the GP, I have begun to notice yo-yo with the GP. It seems like the bypass valve spring has gotten weaker over time. With my 2003 MCS, I thought about the DT bypass valve but never did the mod because of various negative aspects that people had posted. I am interested to hear people's experience with the DT bypass valve on the GP or what Alta might be doing.