Dear Zain bhai jazakallah for ur mesg and appreciation, just trying to spread my limited car detailing knowledge 
Definatly new car kit is not suitable for u as Mashallah u have 3 cars and new car kit not enough to maintain 3 cars
for longer time.
I belive ur both repainted cars paint properly corrected after paint means wet sanding, compounding/ polishing than u just need maintaining the paint
I would propose u following products
1) Ramzan special offer rs2800
It contains
1.4 liter Ultimate wash and wax shampoo ( this shampoo good enough to use on all of ur 3 cars )
a set of 3 supreme shine microfiber clothes ( good enough for ur 3 cars )
Hi-tech yellow paste wax #26 ( good for any medium to dark paint so for Coure its perfect )
2) Meguiars cleaner wax ( good for all 3 cars ) rs1100
Its all in one wax means this wax lightly polish paint, give protection.
Specially white paint become pale faster so to keep their whiteness cleaner wax is very important.
u can use this Wax once in 2 months to keep the paint clean and deep shine.
you can also use this wax on car rims for cleaning
3) Meguiars Ultimate wax rs2100
One of best synthetic wax , specially this wax is good for white paints and will not pale the shade.
you can also use this wax on car rims after cleaning.
4) Meguiars Endurance tyer spray rs950
for all 3 cars rubber tyers only and not for rims
5) Meguiars Quik interior detailer rs700
it cleans interior plastic, vinyl and rubber and give give protection. Can also be used on car exterior black trims.
6) Gold class leather and vinyle cleaner rs950
its suitable for old leather seats however dont use on new leather seats.
We finish our white waxes nor we have Billoxi polishers buffers
We have stock in DHA Karachi and u can collect from there to avoid courier cost
Feel free to ask more
