its common for rx7 guys to run huge a/r.
the turbo names are thrown around quite a bit on ebay. always check the specs against the real deal, even tho often the specs are very vague in the description.
that being said, i wouldnt ever buy one. im a little biased tho since i sell turbos. but the redicously priced turbos will often raise an eyebrow to quality and workmanship. usually built out of cheap parts and low quality control. have they worked fine for some? sure. but there are plenty others that will tell horror stories about them too. dave and i have been selling pte turbos for several years now and have had 1 turbo come back with a problem. even the guy that hooked up the oil lines wrong and shot oil out of the turbo survived lol.