Looking for insight and guidance for 1975 450se

[Yokoi]

Hello Guys, I've owned A 1975 450se

Everything is nearly original on the car

I got a seized up ac and I'm running a shorter belt to avoid it which causes the belt to slip 
I have an nice little exhaust leak on the left manifold 
I've had fuel lines clog
Something in my car is draining the battery
original suspension and shocks has gone bad
leaky steering pump
the car has always idled on the shakier side since owning it
unreliable dash gages


My interior is nearly mint so far, I've vacuumed out all the horsehair filling in the back seats i intend on restuffing it with foam the front is nearly mint with basic dash cracking the seats are nice leather is good only minor rust in the back wheel well of the trunk most of the seals are a bit worn out but stable so far, I definitely intend on replacing them.

I would love help or suggestions on what issues I should I specifically tackle to try to do to bring back to life with this car while keeping it financially realistic I think my budget is 3700$for paint and repairs i got it for free when I was 16 and I want to paint it and get it repaired so it runs consistently healthy and be a nice car to own