Actually, the engines are already armored, specifically the support rings on the nacelles. I think they may look too thin from the current angle but in the top view, they seem a bit bulkier imo.
I made some changes to the already existing textures (namely a slight recoloring and new aztec pattern, Nemesis style), along with some alterations to the pylons. Atolm suggested sweeping them back farther for stronger support and adding a bit of armor.
For those wondering, yes she is indeed 3x the size of the Sovereign
Manitoba - I don't have much in the way of tutorials as most of my texture work is hand drawn (or is it cursor drawn?), aside from details that need to be identical like escape pods and windows. For those I usually use the text option (those pods are really lower case b's in Trill script) or dotted/dashed lines. The aztec is actually a pattern made from one of the stock Taldren textures that I simply modified. If you need advice on any specific texturing aspects, I can probably help out.