For Oerjan and whomever else may be interested in weapons/vehicle design

BTRC's Guns Guns Guns!
http://www.hyperbooks.com/catalog/10012.html
BTRC's Vehicle Design System.
http://www.hyperbooks.com/catalog/20024.html

Both are books purchasable in PDF format online.

BTRC itself
http://www.btrc.net/

I own Guns Guns Guns! and found it to be reminiscent of Striker II or n
versions of Fire Fusion and Steel as far as construction. It is complicated.
But what it gives you is a high degree of integration for various weapon types
into a sort of common framework, and with the vehicle builder I'd imagine you
can then build a wide range of vehicles. The thing I liked about Striker II
was the fact my tank could be built the way I envisioned it (to match a mini
or to create my own image of one) and the stats fell out from the systems I
installed and my hull design parameters and my tech level. Similarly, 3G let
me design some neat weapons and provides conversions for many systems (and
Traveller's Digest produced a 3G conversion chart for MegaTraveller).

One option for more detailed DS2/SG2 conversions would be to build
vehicles with a system like this with a conversion table.