Quick update, I bought sound deadening material and installed it between the carpet mats and inner head shield between the two seats. It reduced the engine "whine" noise dramatically, and since the exhaust noise comes out further down in the car, it didn't change the volume of the exhaust note. Here's a link if interested:
https://www.amazon.com/gp/product/B01KZ5X7KO/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1