Upgrading your bow would give you a bunch of DPS. My budget manti gives you a 14k boost, and if you're prepared to start investing, a 10m bow could probably get you closer to 20k. I probably wouldn't start with that, but it's something you're going to want to do. Once you get yourself a starter set like the budget build, getting a good bow is pretty important. It will often give you some of the best bang for your buck (unless you're severely undergeared in certain areas). As it currently stands, your CC and CD are both great. While DPS is always good, don't forget about eHP. I've made the mistake in the past where I would gear for DPS and totally disregard eHP (I actually didn't even know about it at that point). I got so frustrated that I'd die whenever anything farted in my direction. Basically just remember that while DPS is awesome, a dead DH deals no damage.
If you're going to start scraping away at the budget build, I would suggest starting with the set items. I would specifically start with nats because it gives you the best set bonus. Start with the boots and chest, as they are pretty cheap and will get you the 2 piece bonus. After that, I would probably get the 2 piece inna's set, as they will give you a huge DPS boost (and help fix your low AS). Next would be a mempo because of its socket (great for levelling) and the AS boost. It also gives you a huge amount of eHP. After that, you can basically do the rest in whatever order you want. Nat's ring might be a good choice because of its set bonus, but at this point the major sources of appeal for the items has already been covered.
I'm glad to hear I've captured your attention for so long!
Your mempo is great, don't change it. Your bow is debatable. Before people thought DHs were OP in PVP, you could get a 1300+ DPS 1 soc with dex for reasonable amounts. I had one just like yours, but I traded it out for a 1260 1 soc. I loved it so much that I upgraded it again to a 1374 1 soc. At the end of the day, I ended up gaining ~25k ish DPS for a net cost of 50m or so (and note that I was already 250k+ DPS at that time). Point being, if you set your sights on a 1 soc you might be able to walk out ahead in DPS.
Before now, I always promoted manticores because of their DPS superiority and cost. Now with PVP, it seems that manticores have become the thing and calamities have (indirectly) been buffed massively. I haven't done comparisons myself as I don't have the plans for the new gems, but from what I have read, a marquis ruby in a calamity puts it in serious competition with manticores, especially once you factor in the resource regen and MFD bonus. What I'm trying to say is that if you can afford a new gem once 1.0.7 goes live, you could definitely consider going calamity. It would cost substantially more than 50m though, but keep it as a thought.
The only item I totally with is your chest. You have absolutely no vit on it at all! Apart from in PVP, I don't feel that extra disc is needed, and is certainly not worth losing all that vit over. That disc has displaced your vit which has caused you to trade out emeralds for amethysts, which has hurt your DPS. Other than that, upgrades will come in the form of improving your CC/CD rolls, getting more average damage (like your rings/ammy), and just boosting your dex.
Your budget won't allow you to change your belt and pants to inna's, but I would suggest that you change both. If you're going to use rares, make sure you're capitalizing on the rolls they can give you. By that I mean that they should both have high dex, vit and AR. Your pants might actually end up being better than other affordable rares (they have good vit), but your belt for sure can be upgraded to have AR.
I would probably try to figure out how you can work a mempo into your build. It will give you a substantial amount of eHP, and if you can get a nats reflection, you can keep the set bonus (while also improving your ring). Also consider getting a high damage 1 soc manti with dex. Other than that, try to boost your CD and CC as much as you can.
No worries That's an awesome amount of eHP. Your CC and CD are both awesome. Losing the
attack speed from inna's pants must have done that to you. If I were ever going to use rare pant which is something I've been considering, maybe…) is if I had lacunis to go with them. Reason being is that you're sacrificed both attack speed AND movement speed from inna's. Lacunis generally won't give you the eHP that your rares give you (unless you're loaded), so if you look into them, keep in mind that DPS will be your primary goal. I would look for dex and CC, then grab whatever eHP you can get in place. Or you could just drop the dex altogether and just focus on vit and/or AR on them if it makes it more affordable. I would hate not having 24% MS though, so I'd find a way to make it work haha. If you're not into that and really want better AS, I would look into new gloves. You could get trifectas, or just trade out the CD on it for AS. Definitely keep CC on your gear always. You'll probably get lower rolls with trifectas, so keep that in mind. If none of that works for you, you can always get inna's pants like mine. They don't really compete to powerhouse rare pants in terms of eHP, but they aren't terrible.
Another entirely different route to take would be going with a calamity. With the new gems, I've read/seen pictures of them coming much closer in terms of DPS to manticores. Of course you'd need a pretty good bow and would have to get that new gem, but it's an option that will let you boost your attack speed massively without reworking much of your gear.