Hello, I currently have a b18b1 in my 93 civic hatchback, that is losing quite a bit of oil, from both burning and leaking. So, I planned on rebuilding it and I wanted to get some help on what I should do, before I start doing anything.

First off, I planned on buying a b20, to either do a b20v build or just daily it until I get my b18 rebuilt.
To kind of give some idea, of what I'm wanting to make in terms of power, somewhere around 300-400 hp on pump gas (we don't really have e85 in my area).
I obviously plan on going turbo with those kind of numbers, but not right away, so I would still want to motor to be enjoyable to drive until I do turbo it. If it is similar power to my b18, I'm perfectly fine with that.
I'm really unsure what kind of compression I should go for. I've read that high compression isn't as reliable on a turbo setup compared to low compression, but I know that, a lower compression motor can be kind of sluggish if it is N/A. So, what would be a good middle ground if I plan to turbo it later?
With the numbers I want to achieve, do I need to do any head work whether I go b20v or ls (valve spring, retainers, cam, etc.)
If I rebuild the motor and I change the compression and so on, will I have to get the car re-tuned?
My budget is around the $2500-$3500 area, so if you have any part recommendations or ideas, I mostly care more about reliably more than anything, so if you have any suggestion that would work best for me, I'd greatly appreciate it!

 

 

Ok, a lot of useful information, thank you, I just have a few more questions.

What exactly is effective compression ratio, I understand that it involves your static compression ratio, with a certain boost level, but what does it exactly mean? Is their a number that would be considered dangerous?
Should I go for a ls/v or b20v setup or just stick non-vtec?
If I stay with my b18b1, should I get it machined at all?
Lastly, after the rebuild is all said and done, would it need to be re tuned?