Whoa there Mous, don't beat around the bush, say what you mean
In all seriousness, I like the Dialga tech, but I feel like the only time you use it is against trainer locking decks, as against anyone else it's too slow, as it wastes an attack to level it up. The only situation I can see you doing it is when you can't play any trainers. Drifblim UD solves pretty much every problem you have, and if you run 4x Call Energy (which you should), then you can tech in 1x Lucian's Assignment to get it out right away and surprise the opponent. -- I think you should keep Dialga, don't get me wrong. I just mean add in Drifblim too.
That having been said, I think you should keep the Dialga, but put it down to a 1-1 line since you'll never be attacking with it and the basic is a lot easier to search than the X (Pokemon Collector, Call Energy). Also, you NEED 1 Azelf LA, if your Porygon-Z X or DGX are prized you're screwed. Poke Blower + is also a good idea for this deck, since you can search it out so easily with PZX and it gets you a free prize. Here's my suggested changes:
-4 Poke Healer+ (Kind of out of place in this deck, PZX has a max 150 HP with e-belt and that still gets OHKOd by Machamp, Donphan, etc. -- taking up 4 spaces in your deck is not good, I think Porygon should be more offensive/aggressive)
+4 Poke Blower+
-1 Porygon (Don't need 4; that 4th one will never evolve)
-1 Expert Belt (3 is unnecessary, you can search it out so easily)
+1-1 Drifblim UD (Gets rid of annoying tanks, Donphan, etc. -- I suggest Shiny Drifloon, as it has free retreat)
-1 Dialga G
-4 Poke Drawer+ (Aren't you searching for cards enough already?)
+4 Call Energy (Preventing donks, getting out more Porygons, Dialga G, etc.)
+1 Lucian's Assignment (For surprise Drifblim attacks)
-3 PONT
+3 Looker's Investigation
Looker's has saved me so many times I can't even begin to tell you. PONT is pointless because you're searching for every card you need every turn, so there's no reason you would ever need to refresh your own hand. Looker's gets rid of your opponent's hand, and against SP you always want to do that. Even if they don't have Spray, just forcing them to get rid of their typical massive hand hurts a lot. Getting a mode crash off on a Dialga G tank can also be game winning.
Next is more of a personal preference as I have tried this deck out with SSU and I got four tails in a row so I decided to take it out.
-3 SSU
+1 Azelf LA
+2 Warp Point (Seriously. Porygon has 2 retreat, Dialga has 2/3 - can't remember - the point is you're going to need a guaranteed switch out and it sucks losing games because you flipped a tails on SSU)
So here's what the new list would look like:
Pokémon:
3-2-3-1 Porgygon-z X (TR-TR-DP35-MD)
2-1 uxie X (LA-LA)
1-1 Dialga G X (PT-PT)
1-1 Drifblim (SF-UD)
1 Azelf LA
T/S/S:
2 Bebe's
3 communication
2 BTS
4 candy
4 blower +
2 warp point
1 lux ball
3 collector
2 e-belt
3 Looker's
1 Lucian's
4 evoluter
4 devoluter
NRG:
4 DCE
4 Call Energy
Hope I could help, even if you only take one of my suggestions. I personally use 2-2 Dodrio SV to have some pokes with free retreat I can send up after a KO, but then again if I had an Uxie X things might be different.