Well I have done this this year in an eta. The build is not finished yet.
Start with an 10.2:1 eta motor and fit the 885 head and you end up a 9.35:1 CR. Not ideal but enough unless you want over 200 hp. With the lower CR you will see less benefit from fitting a longer duration cam from what I understand than if you had a higher CR. However there is more to a cam than the duration.. for advice speak to someone who knows like Ant.
You will need to convert to motronic 1.3 and fit the 325i inlet manifold, throttle body and AFM. Without these its not going to do much. Leaving the the eta AFM on my engine left it feeling very flat (even flatter than it is at the moment) at the top end. If you leave the eta exhaust manifold and exhaust on with a 885 head (stock cam, 325i inlet manifold, throttle body and AFM) and one of Ant's 2.7i chips you will get 160 hp @5200 rpm and 186 ft.lb @3800 rpm (assuming my is built right). At 2000 rpm it develops 160 ft.lb so not too shabby and more than a stock eta gives c.150 ft.lb.
Using a 731 head (320i/520i/323i) then you can get more low end torque but the top end hp is more limited to 170 hp ish apparntly but this is assuming you ditch the eta exhaust. Some people have got more but with a MAF, 6 branch manifold and an engine rebuild.
160 hp is not what I hoped for but I have yet to tackle the exhaust and exhuast manifold. The 190hp -200 hp figures quoted for these engine are possible but with more work than and money than I have spent so far. With the exhaust done I will hopefully get more hp, how much I do not know. I took a look at a 325i exhaust manifold today and the down pipe ports look alot bigger than the one's on the 325e/525e, so that could be most of my 160 hp problem.
From the dyno plots I have seen the more pricy builds that push out 220 hp get a bit less torque (150 ft.lb) than I get at 2000 rpm. This is the price of higher hp. So if you want high hp you will will pay for it with low down torque. If you want low down torque you have to sacrefice some high end hp.
However if you get a 325e and its a manual just fit a 3.25 or 3.46:1 diff. It will be quicker than you think and more fuel efficent. You might find you are quite happy with that. If its an auto convert to a manual. Where have you found a 325e, quite common (well moe common than here) in Germany and across Europe.
People on here have got 190 hp out of a 325i but it depends on what kind of car you want. One with easy passing capabilities or one that you have to rev to get it to perform. That is what you have to decide first.
See this post about the issues I am facing.
http://www.e30zone.net/modules.php?name ... ottle+body
