The first build I tried on my SHD-5M and am absolutely loving it. With the speed from the XL275 I am having little trouble flanking enemies and circling around behind an assault. Heating is hardly a problem and the Shadowhawk is remarkably tough.
Built this for myself, and ohhh boy do I love it! Just stick to cover, thanks to the excellent placement of the ACs high on the left shoulder, you can go "hull down" very nicely and still dish out the pain. So far, I've been using the AC/5s on chain fire for more consistent damage, but I should probably switch that up for "close encounters".
I've been using a pretty similar build on the 5M for some days now after looking for different builds than my GaussHawk. That XL275 is a strange engine, though, not giving enough speed for a fast striker, but on the other hand weighing too much (= taking too much weight) for a build which seemingly wants to be a mid range supporter with some close-range capabilities added. For this reason I switched to a smaller engine which still allows to engage pretty early with those AC5s and which gives sufficient speed to not let wounded enemies get away.
When you get the chance you're going to want to sell that XL275 unless you want to master a Raven 3L as it would be useful for the other two variants (they max at a 275 engine). Otherwise you're better off with a 280 which weighs the same as the XL275 but gives you a little more speed.
I'll never sell an XL engine. Case-and-point, I almost sold my XL255 after I finished my Spiders, but I held off. Lo and behold, I found plenty of Cataphract and Shadowhawk builds where that engine excelled (pun intended). Honestly, for most builds that take an XL280, the XL275 is good enough. Also consider that when (if?) dropship mode comes out, you'll want as many XL275/280s, XL300s, XL325s as you can manage.
