Need more torque!

What are my options with regards to boring/stroking a B16A? Keeping in mind that I want to use as many oem parts as possible since aftermarket parts here in europe are just too expensive for me. Also by keeping the original engine I'll have an easier time insuring the car so no engine swaps for me I'm afraid...

well you can just get a b18 rotating assembly and install that.

or even a b20

If I used B18 or B20 crankshaft would I need custom rods to go with it or can I use oem ones? I'm asking because I was told B16 block is slightly shorter than B18 and B20, is this correct? Also would either crankshaft need any machining to fit B16?

Thanks