Tuning modifying 25. avenger

I'm looking to get a little more power to shoot slugs and heavier pellets (28-29 grain). could someone please tell me if opening the barrel port a bit more would give that little more I'm looking for? don't know if I'm ready to do the transport. I'm kind a new to pcp.
 
If I remember correctly (not likely), opening up the barrel port is not recommended. But opening the hole in this piece is (see image below).

Pretty sure AVS talked about it at some point in his teardown video. https://www.youtube.com/watch?v=yHhMJxPzwq4&ab_channel=AirVelocitySport

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First impression of the AV Avenger.

I'm not new to airguns by any means. I cut my teeth on a Crosman Blue streak back around 1960. Graduated to rim and center fire for decades and then jumped back into air guns with a Webley (Brit) Tomahawk and an RWS (German) Diana 36 Deluxe, Fit and finish were exceptional on both.

Fast forward to 2021. I'm old and the right shoulder is toast, so decided to transition to PCP. I never do anything halfway, so purchased three over the past couple of weeks. All NIB. Benj Cayden, Benj Akela, and just for grins, an Air Venturi Avenger. They arrived over the past couple of days, along with the compressor. I've not shot any yet, so this is simply my first impression.

Both Benjamins, appear to be high quality build with attention to detail on the hardware and beautiful furniture. The Avenger, on the other hand, smacks of cheap build quality and resembles more of a kids toy, than a quality PCP? It is almost exclusively made of "plastic", has a hollow stock, and weighs next to nothing.

Why then, does the Avenger receive such high accolades?