hi mate
welcome to the site
for 8k I'd be looking for a blobeye JDM, possibly a spec C or spec D. I think you will struggle to get a nice hawkeye sti for 8k
the tax changed on 06 reg, so blob's are cheaper tax, unless you can get an early 06 hawkeye, but newer than that they are £475 a year tax.
if you look for a 2.5, try to get one that has got a forged engine, there is a known issue with the early 2.5 engine, it's a very low fail rate, but when one fails the owner stands and shouts about it, so it makes them all look bad and a worse fail rate than it actually is.