Here are a couple of things to look out for.
1) I recommend not using the stock/factory/GM Harmonic Balancer.
These things were designed by accountants, not engineers and as you can see from the numerous Harmonic
Balancer threads, they crap out easily, most developing a wobble after 20,000Kms (Or earlier if the engine has seen som high RPM use).
Your best bet is to get a good quality aftermarket balancer (Power Bond) for example.
A lot people recommend and underdrive balancer.
Just be aware that if your car sees a lot of stop start driving, your water pump and alternator will be under-driven.
(Essentially you are robbing power to these, so as you can redirect power to the rear wheels).
This will mean higher engine temps, which will mean the thermo fans will be used to replace the work
that was originally done by the water pump to cool the engine.
With the alternator being under-driven, this in turn will charge the battery less as well,
which means you will be putting a fair bit of strain on your battery provide this extra electrical energy
that is being robbed from the under drive balancer.
In my case, I opted not to use an under-drive balancer, as my electrical system is alreay heavily loaded,
and I commute daily in one of the largest carparks in Australia (Yay for Sydney).
2) A good Harmonic balancer puller is recommended, but not essential.
In a pinch, you can use a 70mm Gear puller, which you can get from Super cheap for around $50,
however there will be a fair bit of messing around with the bolt, and the puller.
My suggestion is to get buy dedicated puller LS2, LS3, L98, L77, L76 (used on fleabay or something like this),
use it, then sell it.
That way you will only be paying for postage, as well as suffering a bit of a loss when you sell the thing.
The dedicated puller makes things a lot easier. (Just remove the bolt, fit the puller, and wind th balancer off).
3) I Highly recommend getting an Arp Bolt for the Balancer.
(Not because of the oooh ahhh factor, or that you really need a super high tensile bolt), but because the Arp bolt
is much longer than the factory bolt.
(This is because the Arp bolt has a huge ass washer that goes between the bolt head, and the balancer).
When fitting up the balancer, this bolt means that you can put the balancer on by hand, and wind the Arp bolt in a fair bit,
then use the Arp bolt to push the balancer in place.
(Instead of trying to bash the balancer on with a hammer, and potentially damaging stuff)
Also you will find the stock bolt will JUST grab when the harmonic balancer is just hand fitted,
and it is very possible that you will strip the thread on the shaft if you try this with the stock bolt.
4) If you have a manual gearbox, then your set (Place the car in to gear with the handbrake on, and you should be able
to crack the harmonic balancer bolt).
If you have an Auto, then you have 3 choices,
a) Remove the starter and use a screwdriver to stop the engine from turning over.
b) Use the starter motor and a breaker bar to crack the balancer bolt.
(NOTE : DO NOT USE the ignition key to crank the motor as the ECU/Smart Start will continuosly crank the motor
until the engine starts, or for 5 seconds).
Instead remove the Fuel Pump relay, and starter relay, and connect the starter terminal directly to the battery.
c) Remove a spark plug and insert 1m of Nylon (clothes hanger) rope trick (Which is the method that I used).
Note this worked for me, however use your own discretion here. Im not repsonsible if you bend a valve or a piston
if you use this method.
