Don't really know what you mean by
Any same performance parts parts that are cheaper
As for the GPU, it is a marginal difference, just as is the price. Essentially, with the 270x you are just paying for an overclock of the 270's stock speeds. So if you are un-comfortable with overclocking or just don't want to deal with the hassle, 270x is your go to card.
For the performance differences, look no further than:
http://gpuboss.com/gpus/Radeon-R9-270X-vs-Radeon-R9-270