yea the DX and LX civics only come with 106, EX are the ones that come with 127 and SI are 160, i think HX is like 115 or 117
yea bolt ons (intake headers exhaust) are cool but they wont give u too much. they will make your car sound great though. i have an AEM short ram, it probably adds around 5 hp but i still like it a lot.
turbo is like the ultimate mod in my opinion

the thing about engine swaps with me is that u cant tell where the engine has been, unless u buy it from someone u know. i am not an engine swap kinda guy i am for boosting ur stock engine : )
www.turbo-kits.com and
http://www.cse.uconn.edu/~yelevich/turbo/turbo.html
just remember if u get an intake and header u probably wont be able to use it later if u turbo, exhaust u might be able to get away with though
if u boost wrong u can blow up ur engine though, intake/headers/exhaust is a very safe mod for most beginnners
if u get an intake, get an AEM cold air which should be 200-300
get some stainless steel headers, cus i heard ceramics crack, from dc sports
and get like a greddy evo stainless steel exhaust
go to modacar.com and look at your options
welcome to car modding : )