In my humble opinion, your tank load outs could use a little work. (Keep in mind this is just how I've found is most effective to run them)
Pask: Don't bother with the extra heavy bolters if you ask me. In 7th ed more things with regular guns are better than few things with fancy guns. 23
Str 5 shots will generally decimate anything you fire at, adding on 6 just doesn't really give you very much for the cost. Bloats pask's price even further if you ask me.
Pasks buddy: The exterminator is an interesting choice, but over all I would say it's not very effective. Auto cannons are kinda weird right now. They're not strong enough to deal with heavy armor, and way too strong and not enough
AP to kill models with 3+ saves. In my eyes, auto cannons are for dealing with, "Light" infantry (4+ save) and transports. Dedicating a Leman Russ to kill either of those is really just not optimal at all. For 10 points a peace you can buy two auto cannon shots that are not twin linked on infantry squads. So if you buy 4, that's 8 auto cannon shots for 40 points. Same thing as before with the sponsons. In my experience they're just not really worth it.
Here is what I would change:
Pask: Ditch the sponsons, keep pask, hes really fun. (Also keep the hull mounted heavy bolter)
Pasks buddy: Remove the exterminator, replace it with an executioner. 3 S7 AP2 3" blats a turn will have your enemies shaking in their boots, wiping out even the most elite infantry models in one or two turns of shooting. The executioner is the only tank I'd by sponsons for. If you have the points laying around and really want them, get the plasma cannons sponsons. The executioner is really a beast of a tank, outclassing the exterminator 10 to 1. If you don't like that, I'd honestly reccomend a regular old battle tank over the exterminator. The only thing it does worse that it is penning transports multiple times.
All this being said, I know you're trying to get an army for cheap, and if cutting points means spending money on more models, then I wouldn't worry about it. Just have fun!