Im looking to upgrade from my d15 but not sure which engines will easily fit and that are not too much money. i plan on upgrading internals and eventually running turbo , which would be the best platform. d16z6 , b16, b18, b20 , h22.

 

I'm not too familiar with what other D motors will fit in, so I'll let somebody else let you know about that.

But for other motors:
ZC
B18a
B16a

If you plan on running a turbo try checking out http://www.g2ic.com and see who is selling their B18a and tranny. You could probably find a complete swap for anywhere between $400-$600. The only problem is most of those guys selling their motors will have high mileage, but it would be perfect for your future rebuild/built turbo project.

 

if your goin turbo i would go with the dohc zc its an easy swap (cuz its d-series) and pretty cheap and good power i gotta a dohc the i plan on puttin a turbo on(one day)