Hello, I've been upgrading my HPI Sport 2 Sprint trying to make it go straight, there was some floppiness on the steering system, I upgraded the front ball cups now it feels pretty steady but still steers so I finally spotted the problem:

The front servo is not powerful enough to keep the steering system straight, so after the turns it doesn't return to dead center so it keeps having a curved course. Also in case there's little force on the road (little rock, bump or sth) it again steers on its own making it super hard to drive especially in tighter situations.

After some tests even lifted in the air I'm pretty convinced it's the stock servo. I looked on ebay and youtube and there are some good ones but pretty expensive (around 50$) can you suggest a budget solution? If there's one...

For e.g. is this worth it or I have to go with the expensive ones? Any experiences?
ebay.com/itm/Core-RC-9016MG-Servo-9Kg-16-Sec-CR494/371847535431?epid=1941984865&hash=item5693d71b47:g :wnEAAOSw241Yh2zV

Waiting for your comments. Thank you :-)