Welp, I am not sure I can change vehicle repairs to use anything else, seems people have tried but noone has done it yet.
Edit, well I found this mod kinda does it, but it seems pretty damn complicated for my poor old brain lol.
https://www.nexusmods.com/7daystodie/mods/1201?tab=description
Don't get me wrong anyway I think this mod is awesome, I only use it on my personal server to mess around with, trying to find the perfect mod combo without going overhaul (I like to play overhauls with no changes, as the dev intends! - Undead Legacy prob my fave, waiting for Subquake to stop changing stuff though before I play with A20 lol).
I am sure I will figure out a way to not ruin my own game hehe

Trying to make it fun though still challenging, hence a bit more focussed on extra skill points early game as the zombies are super tough to kill and hit like a truck.
For anyone interested, server settings and mod list:
Settings:
GameDifficulty 5 (hardest)
Zombies always walk.
Feral sense at night.
No loot respawn.
Bloodmoon disabled (ImprovedHordes is supposed to be amazing)
Mods:
7DTD-Zombiepedia_Skillpoints-7DTD-Zombiepedia_Skillpoints-A20_1.0
ActiveIngredients (really nice QOL)
Advanced First Aid Kit
AGF-A20HUDPlus1.03E
AGF-Backpack72Plus1.00 (edited to have only half unlocked)
Better Quest Rewards
BetterBirdnestLootMid
BoostExpAtNight50
BrazmocksArcheryMod
BugfxFlickerTAA
Devs Traps and Plates
Doughs-PunishingWeather-Core (did not want it easy to wander into snow etc)
Doughs-PunishingWeather-Effects-Light
DxM-Rarities
Faster_Bellows
FRK_Armor_Mods (I have added a few more backpacks to this to work nicely with the 72 slots)
GK Texture Vulture Radiated A19
Harry's Vehicle Mods (installed before VM, unsure if I need it now!)
ImprovedHordes (supposed to be sweet AF, not had one yet tho!)
JaxTeller718-ActionSkills
JaxTeller718-HarsherDeathPenalties (dying was too easy)
JaxTeller718-ZombieReach (insane to play on servers without this, feels like SP now)
KHA20-12CraftQueue
KHA20-15SlotToolbelt
KHA20-3SlotForge
KHA20-AlwaysOpenTrader
KHA20-LockableInvSlots
KHA20-PickupPlants
KHA20-VehicleDamagePatch
KHA20-VehicleSoundFix
KHA20-z15SlotCompAGFHUD
KHA20-zCompatibilityAGF72
Longer Range Shooting
MadWorld_Item_Rarity_Colors
MadWorld_MoreDyes
MadWorld_More_Mod_Slots
Main Quest
MeanCloud__MedStackSizes
OcbPinRecipes (I was spoiled by Undead Legacy so thought this was amazing)
OcbStopFuelWaste
OcbWayPointIcons
Ragsy_Take_Out_The_Trash_V4_A20
SStorageStuff
StatsInDesc
StayClear (did not want zombies respawning in old pois)
TacticalAction (wish I could get rid of the chinese popup! - if anyone knows a decent A20 weapon mod?)
TacticalAction-JaxTeller718-ActionSkills-addon
TelricsHealthBarsV1A20 (this is @%$#ing awesome, so much better than normal health bars - works through bars!!!)
ThunderSn1per Corpse Remover (stops lag)
TOON Stove v2
Valmars Animal Snares
VehicleMadness_Overhaul_Beta2.0 (obviously the best!!)
WrathmaniacsBetterStartingItemsArcher