Well I have to represent my country on two international competitions and i am going to drill two new balls to complement the ones that i already have and i want to know the advice of you guys taking in consideration the 3 patterns that i am going to bowl

well first of all the tournaments:
i am going to bowl the amf world cup in hermosillo mexico: This is a tournament that its known of having a high scoring pattern so maybe its not a THS but its definately not a challenging condition.
And then one week later i have the south american championship and here we are going to bowl on 2 patterns (one long 44ft,and another one short 34ft) preety close of the ones that were used on the world championships on thailand (kegel is going to oil thr lanes).

So my arsenal right now is:
Storm Rapid fire
Storm Agent
Track Slash
Power groove dry/r

I want to add 2 new balls to build an arsenal to cover the three conditions that i mentioned before
I throw about 460 RPM and 17 miles per hour
please feel free to talk about surfacaes that i may need to change to my current balls.
Sory for my english i am from Argentina

I agree with srlunatic, but I might add a few more to that list and retire a couple of yours.. deffinitetly a rotogrip cell or storm dimension a strong solid.. the pearl particle balls he suggested are good ones too, storm shift or the rotogrip mystic.. the storm sure fire(hybrid) is another to think about in this category.. I would look into a stronger pearl also, like a storm gravity shift or a 900 global break pearl.. and for a little dryer condition ball I have been told that the 900 global link is an up and comer to check out.. maybe time to retire the track slash and power gr-dry/r, but I can see maybe were the slash might work on some conditions.. good luck bowling.. slashrr69