I have a base TL 2008. Would the Greddy Evo II Catback fit without the a-spec rear bumper?

 

Yup it should. Its not a dual set-up so no problems.

 

If you look on their site, it will afford you 2 pictures of the unit installed on the base TL.
Select Acura TL and the images will appear:
http://www.greddy.com/products/exhausts/all-exhaust/

Looks like the black filler needs to be removed.

Heel and Toe sells the system and also has pictures of installed system, looks like no problem.

 

it fits on my 06 so it should fit on your 08 but it doesnt look as good without the aspec lip