Hello Peter,
The kit that I have is from G&S Hobbies and it is a five year old kit. The instructions are vague, out of sequense and at times do not make sense. If you have built fron scratch or kits I'm sure that you can get by. I've looked at other methods of building this bird and it doesn't looked like anyone is following the instruction booklet, that includes me. I have drilled the firewall for Sig composite mounts, upright engine mount, Rossi, 5 port engine and Nelson HP muffler. I'm using a MK 12 oz. fuel tank. I have drilled and installed blind nuts for Robart #607 firewall mount retract. It is slimer than the metal SpringAir type retract. I also drilled a hole for the fuel tank stopper. I feel that it is easier than drilling holes for the fuel lines. So far that is where I'm at. I had to stop because I also have to finish an FA/18 twin ducted fan, Electric, from HET.
I will finish the Jet in two weeks and I will continue the DB. I will be using foam core wing and stab from Eureka.

Ben