My SOHC is not chipped but it has the equivalent by reprogramming. If you get the right program you can get an improvement in performance and a little improvement in gas mileage. It is nice to move up the cut off speed also.
I ran some performance test before and after for comparison and can assure you there is a increase in performance. I use a BAMA program and am very happy with it. I have three programs besides the stock program but use primarily the 87 octane performance program.
I find the driveability is improved also with the BAMA program. When I switch it back to the stock program for smog testing, I very much don't like the way it drives and am so happy to get it back on the BAMA program.