Hi Lizzie! Sorry to tell you but Jay W is completely right on the subject of letter ‘E’ used in car designation. Back in the 80s it was Germans that started pushing with fuel injection on mass produced cars more than anyone else and they often marked those versions with either letter ‘i’ for injection or ‘E’ for einspritz (meaning the same but in German language). VW used ‘i’ as can be seen on Golf GTi, BMW used the same as on E30 318i, 320i etc. Mind you, you can also find an early 320 (without i), but that one had carbs, not injection, as you can guess. BMW also used ‘e’ rather than ‘E’ but their ‘e’ on 325e and 525e didn’t mean einspritz – it meant economy. Those engines were tuned to give better economy compared to standard 325i and 525i. Before Mercedes decided to use letters to refer to classes of cars their ‘E’ stood for einspritz as seen on the back of any W123, W 124 or W201 (also known as Mercedes 190). W123 and W124 could be seen with 200 at the back (2000cc, 4-cylinder, carburetor) or 200E (the same engine but + injection), 230 or 230E etc. W201 had on the left side written Mercedes 190 and on the right 2.0 or 2.0E (depending whether with carburetor or injection). Obviously there were other engine choices for it too. Audi used the same lettering as Mercedes, thus Audi 100 2.3 or Audi 100 2.3E, even though the parent company (VW) preferred English to German. Audi also used 5E a bit earlier to let people know the engine in the car is 5-cylinder with injection. Other manufacturers followed in similar way, Ford having Escort XR3 and XR3i, Opel choosing GT and GTE, GS and GSE, but in all those designations, ‘i’ and ‘E’ stood for one and the same thing – injection. At the beginning of the 90s, stricter emission controls and subsequent use of cats made injection necessity rather than exception and as it became the norm there was no need to rave about it any more.
DC, many thanks, i have spent days trawling the net and was starting to think i was losing my mind and the whole E thing was a figment of my imagination
Indeed Jay, and DC, I have trawled the internet and all I find is as I stated before "E" being used by the likes of Ford to signify "Executive", way before injectors for cars were thought of.
It seems to me that at one stage both categories were in use, in different ways, by different manufactures, in Germany and in English speaking countries, because of cause with some "E" was also for "Economy", but I accept Jay you have a Vx manual referring to "E" in GTE of the Astra range that meant "injection".
"i" is certainly the universal badge for "Injection", but of course generally with all "Trim" badges using straight forward letters, i.e. GL, L, CD, CDX, TR, SR, GT, GHIA, ELITE, etc, etc, it generally indicated what each manufacturer considered was the "Trim" level of each model.
At some stage the "i" came in, and as I stated before I concede that the "E" with the Vx Astra GTE seems to have indicated "Injection" before they went to "i", as in SRi, CDi, GSi, with even German manufactures classing cars GTi, and CDi or simply adding the "i" to 320i, 330i, etc. My opinion is that they realised in the mass English speaking world, which of course includes the huge USA car market, they realised that "E" meant "Economy" or "Executive", and "i" was not only already recognised as the "injection" classification in addition to the Trim badge, but was being universally used as such, even with BMW and VW.
In addition in the 1960s, 70s and 80s we saw more purely "engine" badges of "Lotus" were that was considered all important in the market place.
I would suggest that no matter whether or not "E" once stood for "injection" it is now "i" that stands for that engine equipment level in a badging system that once included the old BMC / British Leyland Triumph car "TC" specification to signify "Twin Cam" and "OHC" "overhead Head Cam", along with others that no doubt others of my age group or older may remember for individual manufacturers in the British market. But of course prior to the 1960s Trim level badging of the car was not considered important for sales, instead it was the whole car; it was a Ford, Morris, Austin (cheap end) Austin (Westminster) ,Rover, Humber, Wolsley, Riley, etc (medium) or Bentley, Rolls Royce (expensive).
Now that crucial Trim badging is all important in the volume market sector.

In summary it appears that no definite universal dictionary of Trim levels exists, as manufactures tend to use their own unique terms, such at Merc using CLK in addition to using CDi still, or "E" for a whole "Executive" class of car.

I reckon someone could make some money in compiling a book that defines this fascinating subject over the decades of motor vehicle manufacturing, especially over the last 50 years! 8-) 8-) 8-) 8-)