Sorry, I can't replicate in full using lower parts or torso max out.
Just looking at the numbers, you mech cooling and regen will be terrible. Your cap will be decent in some way. The set up still have some room to add an extra weapon maybe one resist drainer.
Your mech it is a classic mech for free to play starting points. It will be limited for lower ranks, and I will say will get stuck on R10 or lower in today arena condition. At R10 it is hard to win with that mech.
The Nightmare torso, been the basic torso to start the game, it is not a wasted gold instead a good investment. Easy to get and can be used to R1 set ups. Some top players and I mean top 10 players indicate that Nightmare it is the best torso around.
Windigo it is another option to use as second mech without premium part, if not available then make another Nightmare if not luck.
If you don't get Windigo and get Naga, you can also max Naga been close to a Windigo mirror and also easy to replace Naga if you get a Vest because only 1kg on weight apart avoiding having to change your set up.
At EPIC level Nightmare vs Windigo
1-Nightmare weight it is less but less Hit Point
2- Easy to get because start as common part
3- A bit less on regen and energy grant
4- All resists are equal
5- Cooling a little less.
1- Windigo it is harder to get been an EPIC starting point and sometimes very hard to get like in my accounts.
2- People use more because a tiny bit better on cooling and regen but it is heavier. With Nightmare you can compensate that weakness due to weight is less. Easier to set up windigo in some ways.
Just use what you have in hands between those two.
For Naga EPIC it is use more on Energy mechs or even phys mech due to energy base. Resist it is as windigo and Nightmare. It is not a waste. Sure, people use more VEST because resist attributes and easier to assemble.