Joined: Nov 2016
To get more, you really have to deal with the 'weakest link' in the horsepower chain. Right now, with your E6 heads, that is definitely the part holding you back, power-wise. Your TW heads will fix that, but then you have to deal with your speed density fuel injection being off from the better flow. Then the weak link becomes your restrictive exhaust system. So you fix that, and then your cam will probably be the most restrictive part. However - it is also important to note that the stock cam on these, with good heads, makes for a really good street combo. You get a very flat, broad torque curve, with lots of fun from idle to redline, and you can get decent mileage too. Peak horsepower isn't the 'big deal' with a street car. Big *average* horsepower makes for a lot more fun.
Putting in a hotter cam will get you more torque, and more horsepower with those heads for sure. But even if you upgrade, be careful not to just toss in a cam designed for high RPM power with a lot of overlap - especially if you have an automatic. It won't do you any good to have a car that makes tons of power at 6500 RPMs when it's a real dog off the line, and can barely get out of its own way. At that point, your 'weak link' would be gearing and transmission!
I smile a lot. It makes people wonder what I'm up to...