hmm from experiece's from both the motors.. if your cheap and just want to slap something easy & go from the gecko.. i'd say the JDM D15b if your friend, but if you want something a little more torque & play.. i'll say LS all the way.. and just asking iloveboost he built a pretty nice setup for the LS and he was 600+ i think.. and i personally own a LS and I dont like it, but it takes me from point A to point B. and whenever it comes to it, it'll get the job done ....(SOMETIMES) haha.. . to enjoy something and easier to gain more power i'd say LS in my book

and dont get me wrong, i've had a hatchback with a JDM d16b and that thing hulles ass .. and the camshaft in that thing is way better then any other dseries motor i've driven.. hope this souup you up . on gett'n a LS because i do believe you & your girl test drove my buddys DB7 ..