An armour upgrade is only part of your issue here. Wanting to upgrade could mean you want to take on new challenges, are you prepared for a larger turnover of peds to justify buying better equipment?
or maybe you just want to tick along, but be somewhat more protected.
It can take a while for players to accept that taking a giant leap to really take your avatar forward requires more peds. So if prepared to back up your new armour purchase with some nice cash flow, you can finally really start getting the best from the game.
I agree with others here, Gremlin is by far the best set of armour you can get for the investment, add a set of 5B's and you can take on Rex, and Aurlis on CP. Not to mention Gremlin is the best armour for kreltins, which are a lot easier to kill after MA adjustments.
So gremlin opens up a massive door for you.
Hunting such mobs will boost your evade skill extremely fast, it might cost you repairs in the first 6 months, but get through that barrier and you will be well on your way to becoming a quality player.
Gremlin is so under-rated it's almost a joke in EU, it goes cheap becasue it's widely available except foots that costs slightly more. I'm not sure if gremlin still drops after the new Limited range of armours, so get a set before it becomes rare.
Good luck on your new venture, and use your armour to it's best potential, move your ava forward. don't stand still on the same mobs.
Rick
Ps: keep your shogun for drones. In fact add some 6A's and you should be able to take down drone 07 - 09 with the occasional fapping and say 2K dodge skill. Dont need Vigi that has big decay.
