I'd like the share my answer to my (and others') question of whether a Noctua 200mm fan will fit in the TT Core V71. (Ditto a 200mm BitFenix BFF-LPRO-23030B-RP I already had.)
Note than I only looked at this question WRT the front fans (sorry, I plan to put a radiator in the top).
For neither alternate 200mm fan is thickness an issue; while I'm not sure you can tell from the photos, I think both are exactly the same thickness as the stock TT 200mm fans. This is important because the mesh filter is right up against the fans.
And mounting holes are not an issue for either alternative fan either; one of the sets of holes for each alternative fan matched the case holes.
However, the stock TT fan width is perfectly minimal to fit the case, and both alternative fans are wider, and would thus need to be modified to fit.
The Noctua fan's inner edge hole is all one would need; to fit inside the front panel attachments the rest of the four edge extensions would need to be cut off. The plastic is hard and I think resilient.
The BitFenix fan is nearly circled by holes; nearly all of them would need to be cut off the fan. The plastic is hard but also I think brittle.
To complicate matters further, there's the manual warning about using other fans burning out the controller. (Furthermore, when I owned a similar TT case a dozen years ago with only one front 200mm fan, I vaguely recall something I did wrong connecting it burned out the fan; I think I may have figured that out and got an alternate replacement working.)
With all that, I don't think I'm going to deal with modifying alternative 200mm fans to fit the case in the short term.
The pictured Noctua is a Noctua NF-A20 PWM chromax.black.swap
