whats the best brake upgrade for an 08 honda civic ex, not si?

swapping in cross drilled slotted vented rotors with some high quality pads will improve braking distance greatly and also help with fading from heat. it should be all they need for your application.

you could also try changing your stock brakelines for some braided ones

good suggestion man. steel braided brake lines all around would also make a huge difference.

Do NOT put on braided lines, even DOT approved ones can be dangerous dangerous. unlike rubber hoses they are not easy to check for obvious damage and can fail suddenly and prematurely. Dirt gets between the inner Teflon hose and the braided sleeve and will cause a sudden rupture under pressure. The change in peddle feel is minimal, the sleeve is primarily there to prevent the line from getting cut. Don't trust me, google it... The best explanation of why it's better is that they don't expand... While they do limit it, it's at a point way above the pressurse you're going to subject the lines to. It's still a soft hose inside there after all. (Think Chinese finger trap... you can put your lil finger in or your pointer in, but you can fit a banna in it, same concept the braided lines will allow a normal amount of swell but if you go outrageously above operating they prevent swell) Slotted rotors are fine, but cross drilled rotors have a tendency to crack, unless it's a track car I'd advise against getting them, they don't make a huge difference in venting gasses in the first place. Granted it this is to be a dedicated track car, go for. Bigger calipers and rotors can give you a greater area to bite but they increase unsprung and rotating mass, so double bad. Bigger ain't better for brakes, the smallest and lightest you can use and still lock em up if need be is the best. Keep in mind the brakes usually aren't the limiting factor, you're only going to stop as fast as your tires allow. You can have the biggest brakes in the world but it ain't going to matter if you have shitty tires, the single best upgrade is tires. Followed by IMO pads. There is lots of good information on brakes out there, I'd recommend searching for it. Or go to a local AX and ask the guys running your car what they recommend. Also if heat is becoming an issue to where you start boiling fluid, make sure your fluid is relatively new and of decent quality. I personally like ATE Super Blue/Gold as it doesn't take water too fast and it's got fairly high boiling point. There was a discussion I was reading not too long ago and there was some good information posted on some of the fluids available, I'll see if I can find it for you.