Refurbish the BMW 740

Hello dear community, I still have an old BMW 740 in the garage, the old model built in 1996, V8 with 286hp, if I am not mistaken. A classic that I would like to make something for my son. The good piece has 108,000 kilometers on the hump and my first question is whether it is still worth making the good piece. What can everything be broken??? With the catalyst it will be expensive, could it be broken soon? So what I thought: interior is top, like new, just sucked it and wiped it, you don’t have to do anything. Outside: I use a new mirror on the right (the old one ripped out, so the plastic holder) New taillight covers would be used (as in the picture), and on the front maybe new lamps, xenon or something like that. In addition, I would like to install a sports exhaust system, also cut 4 new tailpipes and 2 holes into the rear plastic bumper (as in the picture) Here the picture with my desired “Auspu” ffprojekt” and desired rear lights:http://static.pagenstecher.de/uploads/f/f3/f39/f39e/bmw_0101.JPG Here is the 2nd question, where do I get all the additional parts (mirrors, rear lights, front new lamps, sports exhaust system) and how much will that cost me? Then I would like to sand off and paint over all the slightly rusting spots, or should I do it right away? They would “clean” the bottom surface, wouldn’t they? And here would be the 3rd question, what should I do? I hope you can help me! Yours sincerely, Karl