Servo help required

[Huckster522]

Hi all you knowledgable rc fans, im after a bit of help.

I'm currently running a xxx4 with my 25+ years old Futaba attack R 27mhz radio gear, which after all this time feels comfortable so i do not really want to change it.

The problem i'm having is my steering servo takes about a week (lol) to go from lock to lock and was wondering

1) what would be the best and cheapest (budget is extremely small) servo i could use as replacement?

2) Would a digital servo work with my old receiver?

3) What is meant by 4 channel receiver - ppm mode? (i have seen a new 27mhz micro receiver for sale and wondered if this would help with space in my car), and would this work with my attack R transmitter?

Many thanks for any info you can pass on.

The Huckster