Installed a set of these SSAutochrome headers off eBay. Now I remember why I quit turning wrenches for a living. Whovever designed the bends in these things must have a helper-monkey to put the bolts in. In general I'd say the headers were a good deal for the price (mine were 142.00). I also had to elongate the left front hole. Slightly lower tone, louder in engine compartment, maybe more power, don't know yet about mileage. I recommend the following tips.
1. Allow plenty of time, took me 4 hours with air tools.
2. Buy good hardware, cheap stuff comes with.
3. Coat gaskets with copper coat or equivalent.
4. Compare holes with stock manifolds BEFORE mounting headers, using stock bolts as guides should work. You may have to "adjust" holes.
5. Hold headers in place with stock bolts in "easy" holes and start new bolts with the hole that is closest to the collectorn (2nd and 3rd from rear) otherwise they bind and you cant get them started.