Choosing engine?

[ground_zero298]

After seeing what everybody doing to their r's on here I bought a frame and have started a new winter project. I need to know what kind of engine setup I should go with since alot of people on here have made the jump from stock to fully modded. I do alot of woods riding and alittle hill and road. Also is their any where to pickup stronger gears for the tranny? I have a budget of 2100 for the engine set up. Was thinking a 265 ported for full powerband? Should I also check into a power valve?

Also does it matter who does your engine? or are they all pretty much the same for performance and reliability?