If you've got a 2.0, then get some 2.0 HEs - preferably the SSI SS ones new or used, & use the Triad 2L (or get a stock 2.0 Banana from Dansk if you don't like the Triad, & Dansk also sells the SSI 2.0 HEs).
Then sell off the narrower pipe 1.7/1.8 HEs, since they're constricting the flow on your 2L & robbing a few HP!
Tom
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