Tier 8 buying spree...any tips?

Bullpup...I can't comment on the T54 lt wt, but I can add a comment or two on the T49 based on my limited experience and success (1 MoE on it). I think @owl has an almost 100% damage standing so hopefully he'll chime in.

With a decked out camo crew it can passably passive scout, but not as effectively as some of the others. Early game I utilize it's speed to get to a good viewing spot where I can get a quick side-on shot to dispersing reds making sure to have an exit route. From there I active scout as the map permits or actually sit further back and support pushes. Your HE can consistently do damage to both modules and health. I've slowly whittled away approx. 1000 hit points off of a dug in IS-7 just by hitting him 4 times in the turret. It is also hell on Waffles, French/American side shots and stationary scouts.

It's late game once the reds have been thinned out some that this tank really shines. It allows you to exploit holes and gaps to gain the sides and preferably rears of red tanks conducting drive-by shootings for massive damage. Conserve your health and make sure to slowly move your turret when stationary trying to set-up a shot. It keeps the reticle bloom manageable. Good luck. It's a really fun tank.