I think if I knew more about Nitro cars I would purchase an EK 4 it looks just awesome. You seem to be pretty farmiliar with them so I think it would be a cool choice for you. That huge engine is awesome. My only worry would be about where to use it. In all the videos it seems LOUD!!!!!! If you live in the country or have a place to run it it would kick some $%%$#@!@. I usually run mine here in the suburbs so I cant have something that loud and still have good relations with the neighbors :-(
I dont think the price is too bad considering the engine and overall size of the truck.
Be sure and check out the video of the EK 4 with a 2 speed tranny installed. They used the OFNA Monster Pirate 2-Speed in the EK4. Thats cool that you can do that. Page also walks you through the install.
http://www.midmad.com/ek4/2speed/ek42speed.html
Its at the bottom of page.
Here is another EK4 fansite
http://www.dxdec.com/ek4/index.asp