exhuast help

right now my trx400ex has stock headers and muffler but im looking to upgrade both but im not sure what brand to go with. like alot of people (at least i think) i am on a budget if ya know what i mean. so what is a good brand to go with for headers and muffler that is great quality, good performance, but wont put too big of a dent in my wallet?? also what are some good sites, other than ebay, that have good prices?? im not one of those guys who has to have top notch everything head to toe i just want to rebuild my machine with aftermarket parts and have an all around good machine with power and speed and as ive said in other post i dont race this is just something i love i do it for fun and do a ton a jumping but still would like to have a nice top end speed.
im not totaly new to all of this, my machine is a 99 that i grew up riding and jumping and now im looking to make some upgrades and have a well rounded fourwheeler.

thank you for any info