+1

Gotta figure out how you ride. I'm not comfortable banging the motor off the rev limiter to make power. If you mod the KLX and do the big bore like you're talking about, the KLX will outgrunt that WR all day long. Definately something you should keep in mind if you truly do 50/50 street dirt. Like everyone else has said, gotta be comfortable with EFI on a DIRT bike... doesn't sound that reliable to me... dirt/water/mud + electrical connections = fail to me, but what do I know. Plus you can't fix it when it breaks. You're gonna lose a LOT of money on the trade in of your KLX.

 

I saw a side by side Dyno comparison somewhere, I don't remember if it was on this forum, or the wr250f forum. Basically it compared the stock wr250F to a klx250sf with full muzzy, K@N, and jetted carbs. The KLX came out on top slightly on both hp and torque. That being said the KLX with mods is also cheaper than the wr250f in stock form. However, there is only so much you can do with a klx. There is a lot more potential with the wr250f. Plus being EFI you can add a power comander.
Both the bikes were the SM version, but they are virturally the same as the dirt version.
I would love to have the WR too, but I wouldn't trade my klx for it. The gains arent going to be that huge, and your going to loose a lot on trade. Not sure what your taxes are like where your from, but you don't want to pay them again out here if you don't have too.