The "best" exhaust system can be argued. I have seen several people who swear by TruBendz, MRBP, Borla, FSWerks, Magnaflow, etc... the list can go on and on. It's all about what you think is best sounding to you. As Magus had stated, the Ebay stuff you get will more than likely require some extra work to install it properly. I have seen Ebay headers that are misaligned and cause leaks. As you will hear(read) from a majority of people on here they would recommend the SVT header and that is something I would recommend you as well. It may cost more up front, but in the long run it will be cheaper for you than the Ebay set up. You can pick up a used SVT header, flex and cat or ORP for around $300 and you will know for a fact that they will align up right. But that is just my opinion. There have been several who got lucky and had their Ebay headers actually work but they will also tell you that they had to modify it a bit to work properly. As for the exhaust length, you will need to add about a foot to make the ZX3/5 exhaust work on the sedan.