GM Resources: Prebuilt high-strength implanted blade

A character I've had for ages, since before I got into tabletop gaming, is gradually being built in GURPS. He's a semi-willing dimension hopper, used in a manner not unlike a living, slow speed tactical nuke by the greater multiverse, tossed into worlds out of balance (too far gone, worlds that failed to produce heroes or who's heroes were slain before they could sort shit out, etc). He has several things such as Injury Tolerance (Resilient Physiology), and is generally a life-mimicking construct. In his travels, at some point he lost his left arm in an ultratech world, and picked up a prosthetic with a multi-mode laser and an implanted large knife (katar for functionality). His arm eventually regrew around/through the prosthetic, but the weaponry stayed because he'd gotten used to it being there. At some point I'll probably put the entire character here just as a minor amusement, along with his gear listing at various TLs.

Trying to decide on what specific details of the knife, and the price as an Innate Attack, I did this.
He is ST 20 for damage purposes with the weapon. With minor modification, these stats can be tweaked to represent other strength values. Final prices are at the bottom, vibro versions include the option of using the weapon without the vibro setting activated.

At tech levels where this is more readily available, it would be more efficient to purchase the weapon with 3 points (extra arm: weapon mount (2 pts) and Payload 1 (1 pt)) and cash, listed here as innate attack because it can be taken to any tech level and will eventually grow back if damaged or removed (or can be repaired using any knife available in a very unpleasant manner, which eventually be modified by weird magic-ish processes back to meet the final stats).

Fine katar
2d+1 Impaling (8pts/dice, 2.3d, 18.4 pts) Reach C, -30%
3d Cutting (7pts/dice, 3d, 21 pts) Reach C,1 -20%
Nuissance Effect (cuts open heel of hand, -1 reaction) -10%, Breakable (DR6 -10%, SM -6 -10%, unpleasant repair -5%, -25% total), Temporary Disadvantage One Hand (-15%) Total -50%

Fine Katar Impaling 18.4-80%= 3.68=>4
Fine Katar Cutting 21-70%= 6.3=>7

Superfine Katar
Superfine Armor Divisor (2) +50%
2d+2 Impaling (8pts/dice, 2.6d, 20.8 pts) Reach C, -30%
3d+1 Cutting (7pts/dice, 3.3d, 23.1 pts) Reach C,1 -20%
Nuissance Effect (cuts open heel of hand, -1 reaction) -10%, Breakable (DR6 -10%, SM -6 -10%, unpleasant

repair -5%, -25% total), Temporary Disadvantage One Hand (-15%) total -50%

Superfine Katar Impaling 20.8+50%-80%= 14.56=>15
Superfine Katar Cutting 23.1+50%-70%= 18.48=>19

Fine vibro katar
Vibro Armor Divisor (3) +100%
3d+1 Impaling (8pts/dice, 3.3d, 26.4 pts) Reach C, -30%
4d Cutting (7pts/dice, 4d, 28 pts) Reach C,1 -20%
Nuissance Effect (cuts open heel of hand, -1 reaction) -10%, Breakable (DR6 -10%, SM -6 -10%, unpleasant repair -5%, -15% total), -5% Costs Fatigue, Nuissance Effect (obvious hum) -5%, Temporary Disadvantage One Hand (-15%), Total -60%

Fine Vibro Katar Impaling 26.4+100%-90%= 29.04=>30
Fine Vibro Katar Cutting 28+100%-80%= 33.6=>34

Superfine Vibro Katar
Superfine Vibro Armor Divisor (5) +150%
3d+2 Impaling (8pts/dice, 3.6d, 28.8 pts) Reach C, -30%
4d+1 Cutting (7pts/dice, 4.3d, 30.1 pts) Reach C,1 -20%
Nuissance Effect (cuts open heel of hand, -1 reaction) -10%, Breakable (DR6 -10%, SM -6 -10%, unpleasant repair -5%, -15% total), -5% Costs Fatigue Nuissance Effect (Obvious Hum) -5%, Temporary Disadvantage One Hand (-15%) Total -60%

Superfine Vibro Katar Impaling 28.8+150%-90%= 46.08=>47
Superfine Vibro Katar Cutting 30.1+150%-80%= 51.17=>52

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Fine Katar (6.3+(.2*3.68=.736)=7.036=> 8

Superfine Katar (18.48+(.2*14.56=2.912)=21.392=> 22

Fine Vibro Katar (33.6+(.2(3.68+6.3+29.04=39.02)=7.804)=41.404=> 42

Superfine Vibro Katar (51.17+(.2(46.08+18.48+14.56=79.12)=15.824)=66.994=> 67