Easy. If you want the absolute most classic SVT tone, pickup a vintage SVT, an SVT-II, Skunkworks SVT, MTI SVT or an SVT-VR. All are non master volume and when you turn them up they have *that* tone. If you buddy is more fond of the modern Ampeg tone, the SVT-CL or it's earlier rendition; the SVT-Classic, SVT-AV, SVT-II Pro and Heritage SVT-CL (but that one's definitely out of your friend's budget).All of those amps are master volume, should let your buddy keep is really clean and if he needs dirt he can get it by cranking his pre-amp gain. The non-MVs will distort after a certain point and only get more distorted.
As for that 4Pro there, it's got a tube pre-amp but a big solid state power section. Not too experienced with it.