Do it yourself. If you have a compressor and impact its about 1.5-2 hrs
take off coil packs, valve covers, fan, radiator, water pump, pulley, timing cover, take the rockers offunbolt cam gear(make sure you are dot to dot before u take the gear off), take off cam retainer plate. before you slide the cam out spin it a few times then slide the cam out with the water pump bolts. Slide the new cam in, put the retainer plate back on, bolt cam gear back on dot to dot( its easier to to use the 2 water pump bolts first to get things started then put one cam gear bolt in tighten it down then pull the waterpump bolts and and put the 2other cam gear bolts in)turn the motor over a few times to make sure you come back with the dots lined up (easier to turn the motor over with the plugs out) then pt everyhing back in. you can get the torque specs here
http://www.ls1howto.com/index.php?article=23