With that machine and grinder, I'd start with traditional Italian espresso blends, let the machine warm up for at least 35 minutes, and first learn how to make espresso well. As you're in Toronto, I would recommend Barocco Coffee - https://baroccocoffee.com/ They roast some good Italian blends and as the beans are available all over the city, you'll be able to get fresh coffee.

As for the mods, they're all good, but which is first depends on the machine. Myself, I would probably start with an add-on pressure gauge on the portafilter so I could check and set the over-pressure valve (OPV) - they're easy to make with a bicycle tire pressure gauge and some plumbing parts, but there are pre-made kits like https://coffeeaddicts.ca/products/porta ... -gauge-kit or https://coffeeaddicts.ca/products/porta ... -gauge-kit

Thanks for your advice!
For coffee, I actually plan on getting from my local roaster in Oakville, Carvalho coffee roaster, as well as espresso planet in-house blends. I do see that espresso planet carry Barocco as well so I will add that to my order.

And yes, I do intend on using the PF gauge to set the OPV as the first step. I am going to build with a 300 psi liquid filled gauge from Princess auto (which I can later use to tap into the pump outlet) and a needle valve to test pressure at different flow rate as well. My understanding is I should start by setting it to around 9 bar reading on the PF, am I correct?

The reason for my original question is as a next step, does manual pressure control (adding pre-infusion, tapering off at the end, etc) make a bigger impact or does improving temperature accuracy from stock thermostat give me more return on the investment? Both mods are roughly the same price but since ordering bits from aliexpress takes over a month, I want to start early LOL

p.s. I promise I will practice puck prep first

IIRC, Carvalho uses coffee from their own farm in Brazil. I haven't had it in years as my tastes have changed - and not necessarily for the better!

If you use a needle valve, then I would adjust to eight bars with the needle valve set to the WCE measurement spec of 52 grams of water passed through in an elapsed time of 25 seconds ± 3 seconds (with the portafilter installed in the machine for at least an hour to equalize temperature).

I can't answer your question because I don't know how temperature-stable your machine is and how many different coffees you drink. For example, on the Mokita machine that I have, a PID does nothing as long as I'm happy with the stock brew temperature profile attained by just leaving the machine on for 35 minutes before first use - a PID would only help if I want a different brew temperature for, say, a lighter roast. OTOH, on my Silvia, a PID avoids careful temperature surfing because the brew temperature curve varies so much with the stock thermostat and its location. Different machines behave differently, so I have no idea how much benefit there would be to a PID. Similarly, I had a dimmer and a pressure gauge on the Silvia, but later removed both of them as the coffee didn't taste better (and I had a different machine that was much, much, better at medium and lighter roasts). Different, yes, but better ... depends on the coffee, your taste, etc. If you know that you want to experiment with different coffees and roast levels, then I would do both sets of mods .

Got it!
So play with coffee beans and my skill first before anything else LOL
going to take this into office and it will be on when I am there, pulling 2 or may be 3 doubles a day.

@JRising @baldheadracing
So another testing today....
I have put the boiler back together after the cleaning and I noticed the water coming from shower screen has one or two "streams" instead of drops all over the area. Does it mean that the shower screen is probably toasted and I will need to replace it? I have already cleaned off all the gunk and made sure all the holes are open.

You can tell if the screen has even holes by inspection . I'd guess that is more of dispersion block issue.

ahhh.... in that case I need to bring the custom metal dispersion block up in the priority....
For machines that have a metal block, is it mostly aluminum or stainless? Cannot quite tell from the pictures alone...

ahh, thought I was not supposed to get a stream near the center. If that looks fine I will use as is for now. A one inch long brass bar stock is more than $50 alone lol.... will save for later XD

since i am waiting for the gasket, I am playing with the steam wand on the machine

Just wondering, how long can I run the steam wand for before I would risk blowing out the element?