basically sr20de tend to have higher comp due to its nature of being n/a
anyways, maintenance and fuel consumption is of course less than sr20det engine
since ur gonna buy an sr20de, the maintenance is juz like any normal engine..
change oil when ur required to, belt change bla bla bla..
no issues with running sr20 be it n/a or turbo..
sr20de will of course could not beat the kick of an sr20det stock vs stock.. but the s15 sr20de is rated slightly higher than stock s13 sr20det (214hp vs 205hp)
older s13 and early s14 sr20de do not have variable timing.. the later s14 and s15 do hence the better power and distribution throughout the rev range..
upgrading the engine for higher power would of course need lotsa work (not to mention hard to gain horses compared to sr20det). think of higher comp pistons, stroking, high cams, exhaust.
personally i do like the sr20de.. i've been running sr20det for more than a year now and sumtimes i do have the crazy craving for an s15 sr20de.. put in cams, exhaust, 2.2litre stroker... damn.. at least 250hp i think.. more than enough for ur daily needs..
bottomline, an sr20de is a damn fine engine..
click the link at the bottom for an article from super street mag.. the guy got an s13 with sr20de with 4 throttle.. damn nice
the article
http://superstreetonline.com/featuredvehicles/130_0510_240sx/
the engine bay
the 4 throttle!