I just bought a TD04 turbo that came off a 2003 WRX.
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=33742&item=2439919541
I plan on putting it on my 87 RX. The exhaust impeller is a little bit smaller with more blades than the stock RHB5, but the intake is a little larger and has 6 blades instead of 5. Will I get a HP increase? Or am I wasting my time?