First, Congratulations on your new-to-you acquisition and Welcome to the forum!
Second, take a few, sit back and enjoy the moment, bask in the delights of now being one of the select enlightened few who owns and gets to drive, whenever they want, a 124 Spider.
Third, are you now comfortably knowledgeable in exactly what if any mods might now exist or have been made to your Abarth? Before considering any new mods or add-ons I might suggest you become thoroughly acquainted with any existing mods. Then, with reference to the 'Second' above, spend some time driving your new Abarth as this will help you determine down the road what may or may not be useful to you in the way of future modifications/add-ons/changes.
Fourth, keep a close eye on these forum pages and pretty much all will be revealed in time with regards to what is and is not useful and what may just be eye candy but helps to personalize and make your car 'yours'.
Fifth, your original question is kind of a general one which opens itself up to answers from all across the board. On the other hand, if you have a question or questions about a specific modification or add-on or maintenance or whatever - ask away - you will find the members of this forum to be experienced, knowledgeable and more than willing to share.
Now ......... where are the photos of this new-to-you Abarth?