First off - welcome to the digital age.
Now to your questions - the 9550 is a fast servo when compared to a "run of the mill" analog servo, that would be the first thing you would notice(could be twice as fast or more).
Depending on the setup you have on your car the extra speed could upset the handling when the steering is applied.
If you find the steering to be "on a knife edge" around the "straight ahead" position just go to the expo feature of your tx and dial in 10 or 20 percent of negative (minus), that will "dull" the sharpness of the movement from center to either side, the rest of the setting of the tx are the same as any other car you have set up in a diff memory.
Losi 8ight brushless, Losi xxxt-cr, Losi jrxs type R, Losi street weapon,
Rc10T1 rebuilt, Rc10 "worlds" .Xray T2, Atlas YM-34, Losi XX pro SE
TRC Predator Lynx 2. Tenth Technology super touring, Predator X-10, X-11.
Losi Micro-T, Losi Mini-T, Rc18T, Xray M18
Schumacher Fireblade Evo. All Electric