Boost Controller

Hello.
I'm looking for advice.
I want to install a manual boost PRV controller.
I found a guide on the site, which explains how to leave the EVB attached by connecting the two lower ends together.
So far so clear,
Just install the PRV between the blue tube and the red one coming from the turbo / actuator.
Now the problem is; the PRVs that I find on the internet have a very cheap price, are they reliable?
Plus they have an extra T piece, I don't know if I need it or not.
My engine is quite healthy and has no problems. I set up a gtec 1 and I have thrust problems and I believe that the pierburg does not react properly.
I would like to do this test with PRV.
Thank you.
https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.de%2Fulk%2Fitm%2F223181985993

The Mumby valve works well, you just need a boost gauge to set it up properly. Valve is ebay # 220537042109 :

https://www.ebay.co.uk/itm/220537042109

Or you can get a complete electronic boost controller with built in gauge and new EBV relatively cheaply now :

https://ldperformance.co.uk/product/electronic-boost-controller/

Thank you so much graham.
They ordered the Mumby tomorrow.
Sorry graham I wanted to ask you.
When I bought the gtec 1 on eBay, the seller's name was (traumax)
So I bought a real chip right?
Thanks graham (traumax).

Yes, I think the guy who was selling copies of the older version has quit ebay and moved to amazon marketplace now.

update.
I mounted the booster valve.
Finally my car flies now.
With a sustained boost of 1.1 bar.
Of one thing I'm sure, I've never had a car that worked as well as it does now.
I've always had fluctuations and never a stable boost.
Now and another world.
Thanks for the Graham advice.