I must admit, I'm mechanically capable but..  If I can pay someone a decent price, I would.  As these others stated, it's do-able.
A header needed to be re-torqued after a few miles...  Once installed you may need to have the head pipe (the one directly underneath the oilpan) rerouted.  Look, in advance, where these will end up.  If you pay a legitimate shop they could have this all done for you in a day. And then you'll be done with it.  Everyone loves the works 'custom routed exhaust'.  And your hands never get dirty and your knuckles never get scarred.