b16 or b18 really comes down to preference and how fast you wanna go, along with the amount of money you have to spend.
the b18 will be faster out of the box, down low and up top; but costs more
the b16 is a great motor, although dubbed the "torqueless wonder" is affordable and plentiful in many online shops (SiR2 anyways)
swapping isnt hard, by the way...pretty straigh forward really...dont need a "master mechanic"
http://www.c-speedracing.com/howto/b18cswap/swap.php