Welcome to the thread bro, Masha'Allah you got best Rx8 in the town with some awesome mods..
Well to maintain it, i must say you should buy a good shampoo, few microfiber cloths and some good waxes.
1 - Shampoo (Turtle Ice shampoo) or Meguairs Wash & Wax, Turtle easily available in Pakistan. Turtle one is for 1000. Meguiars are at different rates on different shops.
2 - microfiber cloths, it can be any good 4,5 cloths.. in good brand, go for meguiar's Supreme shine microfiber and Meguiars Water magnet drying towel. Again Meguiars brand is bit hard to find here, also lil expensive. different rates on different shops.
3 - Wax, well again Meguiars, Gold class natural carnauba and Meguiars NXT Tech wax are best combo.. Another combo will be Mother's Step 3 carnauba wax and top it with Mother's top coat.
So you have to Shampoo it, wax it.. and this should be your weekly routine..
before this, i would suggest you to do Clay bar your car to kill oxidation and prepare the surface for further treatment. Well spare some time and Read this thread, i am sure you will get a better idea and interest
but still we are here to help you and guide you. Wait for some senior citizen reply, they will guide you in more detail 