Looking for info on A4 B7 chassis front grille selection , fitment and OEM part numbers, well here you go.
The A4 B7 AVANT platform can be supplied with two different front bumpers and therefore two different grilles.
The S4 B7 only comes with one bumper type which is the S-line version and has very similar design grille as the normal S-line.
and I will clarify the RS4 bumper and its connections to the above shortly.
So to the basics of things.
Any descision one makes towards grille choice etc will be dependant on what bumper is fitted to ones choosen model of A4, as allready mentioned above two differing bumpers are used on A4 and cabs.
If your choosen model of A4 B7 is an S-line bodywork variant then your front bumper will be an S-line item which will also have the removeable foglamp surrounds, also the bumper lower cooling vent beneath the grill is thinner on the S-line compared to the non S-line which is allmost twice the size , this is why the grille depth is relavant to fitment and is another usefull way to determin what bumper you have.
Both A4 B7 fitment bumpers look very similar other than the foglamp surrounds, but there is a big difference in grille dimesions between the two.
The S-line version has a deeper grille and surround and therefore will only fit S-line specific bumpers as the bumper has a deeper apperture,
the non S-line bumper allthough looks to be the same size, the apperture is not as deep and therefore only non S-line grilles will fit,
the two assemblies are not interchangable between bumpers, well not unless you start modifying them to fit which will invlove cutting them to size to fit, not really the best solution but has been done , and to great success by some users but depends to a greater degree on what grille you are attempting to alter, one cant really cut down a s-line grill to fit a non s-line bumper , but it is possible to modify an rs4 grill to fit a DTM dumper for example.
The RS4 B7 front bumper is specific to the RS4 body and therefore only fits the RS4,
but it does share the same S-line grille form and fixings so is a straight swap across the other A4/S4 B7 models using the S-line bumper.
This is a very popular, tried and tested upgrade as the mesh grille design is well suited to the A4/S4
and the fact that it is a perfect fit makes it a problem free fitment.
So now we have hopefully cleared up any issues regarding what fit what now down to the important part.
There are only a few options open to S-line owners with regards to grille choice, you can go with an S4 B7 grille which is similar to the S-line design, the tried and trusted RS4 mesh grill or a third party aftermarket grille ( not many around to be honest ).
Most Audi OEM grilles are matt black or a grey tone, and with differing colored /finish surrounds, if you dont like a specific colour surround it can allways be painted or vinyl wrapped to a color of your choice, you can even change the main grille colour if needed .
Please remember for example, that one can have an A4 Quattro with a non S-line bumper and the same car with an S-line bumper,
the key part is the S-line bodywork option/package as the bumper and grille is relative to that option,
and that applies to a lot of A4 model, not all have S-line kit so will have a non S-line bumper.