LS engines are very easy to upgrade or to add performance parts. The 6.0 is a very common swap. The 6.2 is much newer and will be harder to find. Both require a new computer and in some cases depending on year may require the harness as well. It all depends on what year or generation that your talking about. So the same year of 5.3 and 6.0 can share the harness in most cases but have a different computer. Going from a Gm 800 series to the Gm 900 series then a new harness and computer will be needed cause completely different generations. The engines were updated during that change hence the much more needed parts. Upgrading a LS engine is not expensive, it's a very easy engine to build and work on. This is of course if you do the work yourself. Now if u want to stay with a 1/2 ton then go find a newer 1500 with the 6.2 and NHT package. That truck has the bigger engine plus HD cooling, HD trans and the larger 9.5 instead of the 8.5 rear end. A friend of mine was in the same boat as you and found a newer generation 1500 with the 6.2 and bought it. I look at how much you can do yourself and how much do u want to spend. I would suggest truck shopping only if you don't want to do the work or have the available down time to do it. If you truck shop then may I suggest a gas 6.0 3/4 ton truck. 2007.5 and up are the 900 series and offer a much updated 6 speed tranny and engine power. I don't know the exact weights you are carrying but a 1500 with the 6.2 is a tow beast as long as you are within the ratings. A 3/4 ton gas is so simple to own, requires basic maintenance and has all the HD parts to move and or carry the load. There is a huge difference on how the truck will respond from driving and pulling the load. Not always a performance change but the way the truck will handle or control the load. GM has been using the 6.0 for a long time now. It's just good, it works, pulls and does not complain. You can put a lot of tow miles on that engine for sure. Let me add the the LS engines are all really good and well built. They are so easy and simple in design and have robust 6 bolt mains. Stock LS 6.0 engines can handle supercharging or turbo charging without building the bottom end for performance, they are built very strong from the factory. Sorry to ramble on, just trying to give u all info for u to decide. For me I would upgrade to a newer 3/4 ton gas or the 1500 with the 6.2 again all depends on weights.
