Power plenum upgrade?

Purchased an FX impact from Utah airguns last fall. Shortly afterwards the new FX's with power plenums came out.. 1st of January they offered a special $100 upgrade for my gun purchased on that date, or $300 for people that did not fall within those dates. At any rate it's been 10 months and they say I'm still on a list. Is this reasonable ? Has anybody got one done by Utah since January?
 
I was preparing parts for a next level power upgrade, waited so many months for my local dealers to call me and ended up researching other options.

What I found 3 parts from 3 different sources + shipping each the total cost came very close to the entire PP kit from Krales.

151.88 euros total (the order, shipping, brokerage fee, duty/taxes) and I got it within 4 days UPS (I shall order this months ago I would be done and happy), you convert this to your local currency.
 
You can get the plenum from 910 Airgun tuning $50 but the power doesn’t go up

George, did you try different settings; reg settings & hammer spring settings?

With any configuration, you have different settings and the system needs to be tuned in for any change. 

I have a few more things to do but I’m close to modifying my .25 Vulcan 2 with a PP. It’s coming and I guarantee 58-60 FPE.