So what's an A3 Sportback e-tron? How is it different from a Q3 S-line? What's up with the S/RS models? Fear not, this handy guide to the current lineup is here to help you
MODELS
A - Hatchbacks, Sedans, Coupés, Wagons, Cabriolets (A1, A3, A4, A5, A6, A7, A8)
Q - SUVs (Q2, Q3, Q5, Q7)
In addition to that they have the R8 and the TT lineup.
Higher number usually means bigger and more luxurious, more tech, more power.
ENGINES AND DRIVETRAINS
The numbers (e.g. 3.0) indicate engine displacement in liters. 1.2 through 2.0 are in-line 4 cylinders, 2.3 to 2.5 are 5 cylinders, 3.0 and 3.2 are V6, 4.0 and 4.2 are V8/W8, 5.0 and 5.2 are V10 and there was also the 6.0 W12
FSI: gasoline direct fuel injection
TFSI: same as above but with forced induction (either turbo or supercharger, e.g. 2.0T vs. 3.0T).
TDI: turbocharged Diesel with direct fuel injection
TFSI/TDI ultra: more efficient and clean engines (Diesels have ad-blue)
E-tron: hybrid/electric
G-tron: natural gas (CNG)
H-tron: hydrogen fuel cells
In Europe the displacement badges were replaced with just a number from 25 to 55 that corresponds to the total power of the vehicle. This is intended for better comparison between ICE, hybrid and electric vehicles. For example, 55 TFSI would be a ~350 bhp gas engine with forced induction. Here's a handy link to the scale. The performance models won't be using this scale, however.
Any of these may be followed by:
Quattro: Vehicle is equipped with all-wheel-drive (all other models are front-wheel-drive, except the R8 RWS that has RWD.)
Quattro Ultra: more efficient AWD setup that can be 100% FWD on demand
BODY STYLES
Sedan/Limousine/Saloon: Only used for the A3/S3/RS3 without hatchback. A4 and up are sedans by default.
Avant: Wagon version (A4/S4/RS4 Avant, A6/S6/RS6 Avant)
Allroad: Wagon version with quattro, a lifted suspension and plastic fenders (A4 Allroad, A6 Allroad)
Sportback: Four door version. On the A3/S3/RS3 it adds a hatchback, all other models will keep the Coupé look. (A3/S3/RS3 sportback, A5/S5/RS5 sportback, A7/S7/RS7 sportback)
Coupe: Two door coupé (currently only the A5/S5/RS5)
Cabriolet: Four seater convertible (A3 cabriolet, A5 cabriolet) TT/S/RS Roadster and R8 Spyder are two seater convertibles.
L: Long wheel base version (A6L, A8L)
S-Line, S and RS models
S: Sportier version of their base model (S1, S3, S4, S5, S6, S7, S8, SQ5, SQ7, TT S). More aggressive styling, bigger engine options, tighter suspension, usually only offered with quattro.
S-Line: Base model with the body and styling of the S-model, bigger wheels, leather interior, LED lights as well as options for lower and stiffer suspensions
RS: The most powerful versions. They have little in common with their base model counterparts, aside from the overall styling. They're lower, wider, with big turbocharged l5, V6 and V8 engines, usually only offered with an automatic transmission and quattro. (RS3, RS4, RS5, RS6, RS7, RS Q3, TT RS)
R8: This one stands out of the lineup for obvious reasons.
TRANSMISSIONS
Manual: good ol' stickshift
Multitronic: CVR/CVT automatic transmission
S tronic: dual clutch automatic transmission
R tronic: automated manual transmission (only ever used in the 1st gen R8)
Tiptronic: torque-converter automatic transmission
TRIM LEVELS
Premium, Premium Plus and Prestige: They come with various extra features and luxury items. The higher end cars will only be offered in the Premium Plus and Prestige trims.
Audi exclusive: Option which gives you more variety for interior materials, paint and wheels.
Plus: More power, carbon ceramic brakes, carbon fiber parts (S8 Plus, Audi R8 V10 Plus)
Performance: More power, distinctive interior design elements (RS6 Performance, RS7 Performance)
Hope this was helpful, written on behalf of reddit user HeavyHDx. You can see his original thread HERE.