Unit IDs:
 Currently, TA:T uses 507(?)(as of v1.8) of the available 511 unit IDs, meaning
 that you can safely add up to 3 additional units without risk.
 It is technically possible to add up to 512 units to the game,
 but this usually results in bad things happening... especially
 if you have TADR installed, since it uses up a unit slot.

Unit IDs added in the Twilight Betas since version AA 6.0 official:

UnitName=ARMNANOTC3;
Name=Advanced Fortification Turret;
Description=Repairs/Fortifies Large Area (Cloaks);
UnitNumber=9906;

UnitName=CORNANOTC3;
Name=Advanced Fortification Turret;
Description=Repairs/Fortifies Large Area (Cloaks);
UnitNumber=9907;

UnitName=ARMMANT;
Name=Courier;
Description=Armored Ground Transport;
UnitNumber=604;

UnitName=CORSCORPI;
Name=Emissary;
Description=Armored Ground Transport;
UnitNumber=607;

UnitName=ArmPomPom;
Name=PomPom;
Description=Anti-Air Laser Flak Kbot;
UnitNumber=227;

UnitName=corbarrel;
Name=Aries;
Description=Anti-Air Laser Flak Kbot;
UnitNumber=1235;

UnitName=TalGate;
Name=Astria Porta;
Description=Provides Instantaneous Transportation;
UnitNumber=7777;

UnitName=ARMNANOTC4;
Name=Nano Repair Turret;
Description=Repairs in large radius;
UnitNumber=9908;


Unused Weapon IDs:
138, 139, 140, 141

Unused Weapons:

63 [CORMINE5]


Weapon IDs added in the Twilight Betas since version AA 6.0 official:

235 MEDIUM_UNITEX (Was CORTRONM_WEAPON ID 235)

119 PT_MISSILE (Was CORVTOL_MISSILE_A2A 119)

155 EXPLOITER_LASER (Was ARMESTOR_BUILDINGEX 155)

125 MOBILE_LRPC_CANNON (Was ARMESTOR_BUILDING 125)

109 BERSERK (Was CORVTOL_MISSILE ID 109)

76 HOVER_ARTILLERY (Was CORSFIG_WEAPON ID 76)

198 FIRESTORM_WPN (Was CORSH_WEAPON ID 198)

75 VENOM_LASER (Was ARMSFIG_WEAPON ID 75)

68 CORVETTE_GAUSS

130 AK_LASER

131 PEEWEE_EMG

132 JUGGER_FIRE

133 KROG_BEAM

111 ARMFLAKLASER

35 CORE_DOOMSDAY_SECONDARY (Was CORATL_TORPEDO ID 36)

242 PANTHER_MISSILE (Was ARMEMPM_WEAPON ID 242)

113 SHIVA_CANNON (Was CORVTOL_ADVMISSILE ID 113)

114 SHIVA_ROCKET (Was CORVTOL_ADVMISSILE2 ID 114)

134 SHODAN_LASER

135 CORE_DOOMSDAY_TERTIARY

136 MECH_RAPIDLASER

137 THUNDERSTORM_WPN

188 ARMANTAR_LASER (Was armmine5 ID 188)

105 HELLBORE_CANNON (Was WIND_GEN ID 105)