Personally - don't do it 
In the snobbiest way possible, i think when people start to add aftermarket stripes to these cars it degrades the model's brand image - and becomes less desirable. You have to be SO careful to pull this off and make it look OEM+ rather than essex-carpark. Have to admit there are some 'not-bad' examples listed, i agree the ones that are highly modified you can probably make it fit in, but on a stock car it just doesn't work imo.
Don't mind some out-there mods that are considered extreme for a bit of diversity but adding bad stickers for your supermarket run... you may as well add dulux matt paint and glue on some cardboard body kit components.
On the other hand - the ///M stripes and fun stickers for LeMans / Road trip events are cool, and acceptable as it's a special event where you're meant to sticker-up.
Just my two cents, don't take any offence
In the snobbiest way possible, i think when people start to add aftermarket stripes to these cars it degrades the model's brand image - and becomes less desirable. You have to be SO careful to pull this off and make it look OEM+ rather than essex-carpark. Have to admit there are some 'not-bad' examples listed, i agree the ones that are highly modified you can probably make it fit in, but on a stock car it just doesn't work imo.
Don't mind some out-there mods that are considered extreme for a bit of diversity but adding bad stickers for your supermarket run... you may as well add dulux matt paint and glue on some cardboard body kit components.
On the other hand - the ///M stripes and fun stickers for LeMans / Road trip events are cool, and acceptable as it's a special event where you're meant to sticker-up.
Just my two cents, don't take any offence