Engine arrived very well packed with no damage from shipping. Dropped right in to my Husquvarna lawn tractor. Plugs were the right size and engine mounts were perfect. No modification was needed. I started putting this engine on at around 10am and was cutting grass before noon. Really simple. Add oil to engine, it is shipped with very little. The engine I replaced was 23 horse, and this is 20. Not much difference really. This one seems quieter, but perhaps that's because I had to take all the shields off the old one due to mechanical problems...