[KTL]

You would be wise to space out the rears if you want to keep the car balanced the way it way it was previously. You can go with a 930 spacer and long 72mm studs to get the rear spaced out.


Assuming you started with 16x6 front, 16x7 rear

Stock SC/Carrera
1361mm front (53.58 in.) 6 in. front wheel with +36mm wheel offset
1367mm rear (53.82 in.) 7 in. rear wheel with +23.3mm wheel offset

With ET 23mm 7's on all four corners your track widths are theoretically as follows:
Add 1 inch of track width in front which = 1/2 in per side, when each front wheel width grows to 7in. wide

Add the reduction in positive offset when switching to the 7 in. wheel, which = 36mm - 23mm = 13mm additional track width increase per side = 26mm total.

So the net result is a 1 inch + 26mm additional outward offset of the wheels. Call it 51mm total.

Now you've got a front track of 1412mm and the rear track width remains the same at 1367mm. So the front is 45mm wider than the rear.

To deal with that, you should install at least the 930 rear spacers (28mm thick) on your 7's , for a total track width increase of 56 mm, and then you end up with the rear being 11mm wider than the front. That is, if you want the track widths to be nearly the same difference as it was originally before you changed the wheels.

Or, if you want the car more tail happy for AX, leave it as is. I don't know AX setup since i've been primarily road course driving my cars.