Nope, pistons gotta come out from the top. Don't even start thinking about that yet.. You didn't mention the plug wires and resistor ends. Did they get done? If you are really convinced that adding a few PSI to each cylinder is what you need then rip into it. If your cylinders and pistons are not worn out of spec. (I doubt that they are), then it's ring replacement, cylinder honing and while your there, check the connecting rod bearings and wrist pins in the pistons. How much do you want to spend!! Please advise re: plug wires.
BTW a couple of other thoughts. Fuel system is one. Dirty injector, low fuel pressure. Are all of your vacuum lines back where they should be. A remote but possible cause could be a worn lobe on the cam. Did they check the cam when they had the head apart. Did you have the valve springs replaced? Are you confident that the valve job was done correctly? Persevere my friend, we'll figure it out.. 18 MPG is not very good mileage, but you did say stop and go was your forte..
------------------
Jeff L
1987 300e
1989 300e
1987 BMW 325

[This message has been edited by jeffsr (edited 04-23-2000).]

[This message has been edited by jeffsr (edited 04-23-2000).]