Where's the SR to match the top KA? I think it needs to be asked where's the KA to match the top SR. I've never seen nor heard of an 800hp, or even 700hp KA (the KSP engineering S14 puts down 800 rwhp, the Jun puts down 700hp). You talk about how if Duy's race car was gutted it "would" be faster than the hyper lemon silvia. Well, the fact is, its not. The fact is that as far as I know, there is no KA that has broken into the single digits. There are plenty of SR's that have. This, of course, doesn't say that the SR is the better engine, but just saying that just because the KA has all this potential, doesn't mean its better than the SR. Potential is theoretical. The SR has been proven time and time again that its a bad ass motor.
There's a 10 second Miata, with a turbocharged BP (the 1.8 liter Miata engine that puts out 140 crank hp). Does that mean the BP is a great engine? The Miata's a street car too. If we're talking about accomplishments, I'd say the KA is at about the same level as the BP <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/tounge.gif" border="0" valign="absmiddle" alt='
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Yeah, to clarify, that was a joke. But you can't say the KA is better because of accomplishments or because of potential. I'd say its impossible to say which of the two is better - it depends on your use for it. It's really the same situation as asking whether the 2JZ-GTE or the Chevy 350 is better. The one think that can be asked, is which suits your purposes? Do you like the whine of a huge turbo, or the rumble of a V8? High end hp, with lag, or a whole lot of low end, with a low redline? Take your pick.