Wheel Fitment, unsure about offset

[csnowden77]

Hello folks, new to this site but was wondering if someone could help, i have a seat leon Fr+ 2012, currently got the iberia alloys on that come standard fitted with 225/40/18
Im looking to buy a set of Audi RS4 Alloys, these are 7.5j x 18 H2 ET 54, I believe the iberia alloys are the same but an offset of ET45,

Im wondering if this much of an offset will effect the car or will this be a straight swap of alloys?

Also how can i tell the alloys are genuine Audi alloys, they are stamped with RONAL 2428 if this helps but also have the Audi rings marked inside too?
Thanks alot in advance!

 

[RD-Woo]

Also how can i tell the alloys are genuine Audi alloys, they are stamped with RONAL 2428 if this helps but also have the Audi rings marked inside too?

Not genuine wheels if is it not stamped part number inside
Also, the Audi RS4 center bore is 66.6mm, Seat Leon FR center bore is 57.1mm