its all in your own opinion. a v8 is a good option that will give you plenty of power but as has been said, you may find other weak links in the system quickly with the added power. another option is the steep gears, this is a good option to as it will work better with what you have engine wise but will require different axles. this is my opinion is good though as stock axles are weak anyway and this will get you new axles and better driveability you want. there is the next option which is what i did and pump up the little 2.5 for everything it has with a large rebuild, and use mild gearing. then there is the last option and my favorite, drop in a small diesel engine like a cummins 4bt. like i said lots of options just personel preference