most likely swap or built motor. theres a blue del sol around here ive run a couple times. loud ass exhaust. this last time we we went he was maybe half a car length behind me, i was in third gear (dont remember how fast, but i was right in the sweet spot ready to pounce) and then i heard him get on it so i let him get a little bit of a run and as soon as he got to my back bumper i punched and put a half a car on him again, but then after that he hung right back there thru third and most of 4th before i shut it down. we got stopped at the next light and he was actually surprised he hung so well. he wouldnt tell me what he had but he did say he was all motor and running 11.1 compression ratio. he seemed like a cool guy so i gave him props.
oh, and im cobb stg2 +RA gears