Following my OSR GURPS idea I'm taking a couple of those items and applying them to Twilight: 2000 4th edition. It's pretty much GURPS attributes and attribute levels and GURPS skill levels and then use T2K4 modifiers x4. Everything will be T2K4 rules except once you have to make rolls and that uses GURPS, hence why attributes and skills are scored on GURPS levels.


Attributes (4d6, best 3; avg is 12.3)
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A = 18, B = 14, C = 10, D = 6

ST (use for T2K4 STR) - Close Combat, Heavy Weapons, Stamina
DX (use for T2K4 AGL) - Driving, Ranged Combat, Mobility
HT (no T2K4 equivalent)

IQ (use for T2K4 INT) - Recon, Survival, Tech
Will (use for T2K4 Stress Capacity, CUF)
CHA (use for T2K4 EMP) - Command, Medical Aid, Persuasion

HP = ST (use for T2K4 Hit Capacity x3)
FP = HT (reroll costs 1d6+ENC FP)
Stress = Will (use for T2K4 Stress Capacity x3)
CUF = Will
Rads = 1d6

Starting Skills: A = +8, B = +4, C = +0, D = -4


Encumbrance
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1 T2K4 Encumbrance Unit (EU) = 3kg

GURPS Basic Lift = STxST/5 in lbs
Basic Lift in kg = GURPS Basic Lift / 2.2
Basic Lift in EU = GURPS Basic Lift / 6.6 = ST^2 / 33

T2K4 C STR = 10 ST = 20/6.6 = 3 EU.

ST 18 = 10 EU, ST 17 = 9 EU, ST 16 = 8 EU, ST 15 = 7 EU, ST 14 = 6 EU
ST 13 = 5 EU, ST 11-12 = 4 EU, ST 10 = 3 EU, ST 8-9 = 2 EU, ST 6-7 = 1 EU

Combat Gear = Light ENC
Backpack = Light ENC

GURPS ENC Levels (mostly used for Pushing Rolls)
None (0) = BL (EU)
Light (1) = BL (EU) x2
Medium (2) = BL (EU) x3
Heavy (3) = BL (EU) x6
Extra-Heavy (4) = BL (EU) x10


Skill Rolls
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Success = 1 T2K4 success
Success by 4 = 2 T2K4 successes
Crit 4+ = 3 T2K4 successes
Crit 3 = 4 T2K4 successes
Fumble = damages equipment (decrease reliability rating)
Fumble 18 = damages equipment x2
If no equipment then 1d6 FP

Pushing Rolls
1. Spend 1d6+ENC FP
2. If out of FP spend HP (STR/AGL skills) or Stress (INT/EMP skills)

Modifiers: GURPS modifier = T2K4 modifier x4

CUF rolls: use Will, Unit Morale is a modifier like skill (+8 to -4)


Combat
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1 T2K4 damage = 1d6 GURPS damage (HP or Stress)