Yeah bro appreciate that. But I don't think there would be any big displacement car with manual transmission in the future without paying a fortune.
Well what is your target top speed actually?? 220, 230, 250? If you want fast manual car, then just sell off your Inspira and buy either real Evo CT9A, Subaru Impreza WRX, Nissan Silvia S15R, Civic FD2R, or some Renault Megane RS, all are manual cars that can reach 250 or more with only 2.0l engines so no need big displacement.
If you just want to add a bit more, then just the normal remapping, exhaust and intake work coupled with lightweight rims, maybe you can gain like 10% more real power and 5-10kph more top speed. But to do all that, you may need to spend a few thousands already, that's why some may say it's not really worth it. Swapping engines may give you electrical issues, coz might simply take short cuts and just cut and tap wires here and there, then bypass some other things.
Anyway IMHO top speed is also overrated, acceleration and the whole packaging of the car to make it fun to drive is more important.