The first step is to get rid of a wife that wants you to get rid of a TMNT original cab.

From there, pretty much is the same thing for best results (low input lag + compatibility with demanding games):
CPU with 4ghz+ Overclocking capability + AMD/ATI video card from 2012-2016 timespan (supported list is on the crt-emudriver post/thread).
Recommend:
Any I5 or I7 Intel Processor from 2014 ( i.e I5 4690k/ I7 4790k) onwards with Overclock support ("k" digit after number) with matching motherboard that allows at least basically, no-voltage changing overclock.
AMD R9 380 (last, easy to find gpu with analog support. Some R9 390 have it but they're harder to come by, and a r9 380 is pretty much overkill already)
bear in mind this setting would be a "enthusiast setup". You can go for a lot less (specially in the gpu department) and save for other things, like SSD storage for faster system/rom loading.