I have ran vspec for the last 2 years. go with the ebmods 21 Vspec. Mount that up with a OS2050 or the OS2060 and you wont be disappointed. I ran a EBMODS in my heavy jammin crt till I got my OS speed.
Had no problem keeping up with the lighter truggies like yours.
The 28's will be more than enough also I have no experience with either of the 28's you are talking about. but both are good manufactures.