The E300 has a de-tuned DIRECT INJECTION 3.5 liter engine from the E350, not an old port injection engine. This engine is also used on C300. Unfortunately, the Canadian MB website doesn't specify the type of injection used on this model. It can be checked on the US webiste though for the C300 model.
You are correct. I'll have to fix that up
Being a detuned version of the same DI engine makes me ask "Why?". Do they really cut costs detuning an existing powerplant for a base model ? Seems pointless...
This has nothing to do with cost cutting. This is just to ensure that there is enough daylight between an E300 and E350 so that both have their place.
Lets say the E300 had the old 350 (268hp). Now the ~300hp DI 350 doesn't look like a big enough step up (although it does have better fuel econ, which is good, but that's a really weird selling point for engine upgrades).
So then you have to squeeze more power out of the DI 3.5 which perhaps they don't wish to do for various reasons:
-technical limitations
-keep some in reserve for late model cycle upgrade
-have to keep distance between this and the E550 (old M273 5.5L, updated from the one in my CLK, but still old and port injected)
So for the above reasons, plus the fact that the 528 is around 240hp IIRC, means that a detuned 250hp engine makes perfect sense.