It's not too hard. You need to unpack data for the RSS and ASR 641, then copy over the driver3D.ini file from the ASR data folder to the RSS one. Then copy the all the crew, helmet and suit .dds files from the ASR Prost and Mansell skin folders and put them into the RSS 01 Ferrari and 02 Ferrari skin folders respectively. If you want it to work in CM showroom you also have to rename the data.acd file for the RSS car to something like data.acd.old OR repack the edited data. But if you race online, the first option is better as you can restore the name to data.acd for checksum purposes.
BTW the skins I use are here:
Version 1.0 Ferrari skins for the RSS Formula 1990 Get the car here! For the Good Year Eagle F1 tyres for the RSS formula 1990 Just copy and overwrite the files in your extension folder. To revert to the basic tyres use the files in the backup...
www.racedepartment.com
I think those are the ones you have too.
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