Hello and welcome to our Forum! Glad to have you with us.
Here are a couple things you should get clarified or ask about:
1) just because CZCustom has the Shadow T in stock doesn’t mean they have done all the mods that make a great competition weapon or even the mods you want. So if you buy the Shadow T the question is have they smoothed out the trigger pull, swapped out the springs, replaced the hammer, replace the trigger (say the flat one for the curved one, and what have they done regarding the take up or travel length on the trigger? Is all that included in the price they are asking now or do you have to pay extra for any or all of that? Personally I have no idea, and this is something more or less that anyone thinking about upgrading or modding their firearms should think about before actually putting your/their money down. Ask every question you can think of, to make sure there are no added on costs after you think you have a price you can live with. And I am talking about ANY, brand or model.
2): Consider this also, you have had that Shadow T for 2 years and you know everything about it, you have built 2 years of muscle memory using it, you know how it feels and balances in your hand and it's little eccentricities. Buying an entirely new weapon though similar, is going to make you have to learn an entirely different sent of everything I mentioned. No two pistols are built the same way unless costumed from the bottom up and even then there may be small differences or quirks between one and another. Your model is at least 2 years old, which means anything including the metals and or alloys it was made with may/could have been altered as new techniques have come into play. It may weigh more or less, how much is anyone’s guess. And yes sending you present weapon in to be modded is going to do some or all of that but with much less impact on how you handle, and shoot your weapon.
So it more or less boils down to investing in making your well used and loved pistol even better, but still essentially the same pistol your body and mind have grown accustomed to. Or do you buy an entirely new weapon, and have to learn it's little foibles, and everything that goes with what I said above. Personally I'm 2 things, Lazy with a Capital L, which means having to learn how an entire new weapon works and handles sounds like work. And I am Sentimental about some things. I still have the very first CZ I ever bought, and a couple years ago I passed it on to my daughter when she went to college and then even further away to Austin and Graduate school. I have way more than that one CZ, and have been collecting them over the years, but instead of trading in my old, well-worn and comfortable friends I have them worked on when and if they needed the help or it seemed like a good idea.
But I am one of those people that when we have something that has taken care of us for so long, rarely let us down even when we have forgotten do things to help it work (oil, cleaning, etc.) it's still there for us. I was once told (back when I had the same car for about 10 years, and it had been rode hard and put away wet, more times than not, and I refused to get rid of it. A drunk driver did that) that I had the same attitude towards some things that the Apache's had/have for their horses. They ride them, use them until they die then eat them. (sort of a Honoring them and their loyalty and service I think){and don’t wonder, most everyone I have ever said this to, doesn’t get it, so you aren’t alone if you don’t}. So all that/this last part is most likely meaningless, I do ramble some times, my point is that what you do depends on how you look at things and think that having something that has worked well for you, upgraded, and in result a smaller or less learning curve getting to know it. Or do you retire it, keep it for plinking now and again, and buy a totally different model (yes I know, same basic name/model, and so on, but totally new) and then have a longer learning curve getting to know it as well as you know your present pistol.
Your call, and I totally get the money thing. Things are tight and getting tighter, but no matter which way you go, whether taking a risk that another part will wear out and have to be replaced, or buying new and partly if not totally unknown. So there ya go my 2 cents in MHO.