e5 and e6 go for between 6000 to 7000 for a good one but if you look around and you now what your looking for you can get them a little lower, im lucky i learnt all about them a few years ago and have now built up 3 4g63t evo engines up, my latest was my e4 i put a really nice e6 engine in that i built from the crank up, ive posted b4 i honestly think the 4g63t engine goes together like lego very easy to build and parts are very cheap, if you want to go posh coswoth make , crankshaft, pistons and rings , the whole 4g63t block, cams , so alot of the engine, are you can buy a cosworth shortblock