I want to get some Keeley modded pedals and was wondering which one would get the tones I want the best so I can get it first. I was to get a Thrash tone, i.e. Testament, Megadeth, Metallica. and the Overdriven tones of Randy Rhoads, Van Halen, Alice in Chains, Iron Maiden, and Dream Theater. As well as blues such as SRV and ZZ Top, and classic rock such as Aerosmith and Zeppelin. I would like to buy the following:

Keeley TS-9 Ultra or Boss BD-2 (which one is better for what I play)
Keeley SD-1 Stacked Mod
Keeley MT-2 Twilight Zone Mod
Keeley DS-1 Ultra Mod

Which one will cover what I like to play the best?