Components for toy car hacking

What to do with a Nucleo board STM32 L053R8 (Ultra-low-power ARM Cortex-M0+ MCU with 64 Kbytes Flash, 32 MHz CPU, USB) ... Some toy car robots ??

Searching for components:

• the keywords are: DIY, Starter kit, Robotics kit, Breadboard kit, learning kit ...
• OM electronique http://www.omelectronique.fr/ (Grenoble)
• Competitive eBay shop and nice 48h shipment
• Amazon, eBay, banggood aliexpress dealextreme ...

Motor

About 130 models at DigiKey.fr. 

Lego

Lego has a nice collection of motors:

• M fast but not powerful (15€)
• X well suited to propulse a car (25€)
• XL slow and too powerful? (20€)
• Servo Moteur quart de tour a gauche, quart de tour a droite (30€)
• Finally the pack (32€) piles, inter, lamp and a motor, but which one?
• Battery box for 6 AA (13€)

Well, might be easy ... too easy? Will it be adapted to the power control shield on the Nucleo??

For the record Lego has also a pneumatic kit (80€).

Starter kits

Complete car or robots

• Impressive kit at just 70€: Elegoo Kit Smart Robot Voiture Car V1.0 avec Tutoriel en Anglais Arduino UNO Project avec Des Lecteurs à Quatre Roues Motrices, UNO R3, Line-cruising Module, Capteur à Ultrasons, Bluetooth Module, Télécommande, ect 
• Robots: https://www.digikey.fr/products/fr/maker-diy-educational/robotics-kits/942

Kits look really nice, but you assemble and then what. Puzzles are not my kind of fun. A custom, original and risky robot will be better.

Basic components

• Breadboard kit: Elegoo at Amazon and same at eBay.
• Looks like AliExpress has some cheap breadboards and components. (shipping might be slower so.)
• "dupont" cable at eBay
• breadboard "platine d'essai" at eBay 
• Simple alim for when there is no dedicated laboratory alim
• Resistors at eBay