(FT) UIM and DERFACs

I'm working on a set of rules for "SFBing FT" (without all the
rules problems, mostly for making SSDs) and someone
mentioned that I forgot about the Ubitron Interface Module
and D.E.R.F.A.C.S. (some acronym about improved disruptor 
range and hit chance).	These are for Klingon ships, but 
"other races" experimented with similar systems but never
installed them.  SFB explains UIM as some sort of focusing 
crystal or matrix that burns out easily, the Klingons used
them to improve disruptor and their low-powered phaser
damage potential to compete with the Fed's photon torpedo
and stronger phasers.

Here's ideas I want to bounce off your heads:

UIM: +1 to hit for ranges up to 30, but weapon automatically is
damaged and fixable.  Only for pulse torpedoes and B2s & B3s
(may want to use only for pulse torps).
Use is optional at time of firing.
No change to cost.
Alternatively, if any die to determine a hit is a 1 then the weapon
is damaged and fixable. The cost multiple is increased by 1.  Or,
should this have no damaging effect on the weapon?

DERFACS: extends the range of pulse torpedoes to 36, chance to
hit from 30-36 is 6.
I don't know if I want to make it a separate fire-control-like icon that
can
be damaged or increase the cost of the pulse torpedo.  Increasing
the cost is probably easier, say +1 to the multiple, although I think
this is too costly for a small increase in range?
Increase the mass by 1 (becomes 5 + 1 per arc)?

So, a pulse torpedo with both UIM and DERFACS can be a deadly
weapon (at least in the hands of someone who doesn't roll lots of 1s).
So, if using the cost increase options, it would cost mass x 5.
Too much?  Not enough?

Glen