[Need a little help in deciding]

Hmm alright I guess I will get the Deka first and then go from there. Thanks for the help

[Need a little help in deciding]

Alright guys I know this kind of question has been asked before but I just wanted to make sure what will be right for me. I already tried searching for a long time but haven't really found my answer.

So I just bought a Sundown SAZ-2000D for my subs and I already have a JBL GTO 1004 for my mids and highs. So what I am trying to figure out is if I should upgrade my alt or just get a second battery. I already have a yellow top up front and I have the stock 145 amp alt. My system would be around 2400 watts but judging by how much the SAZ-2000D is underrated I'm guessing my system would be close to 3000 watts. I was first thinking about getting a Deka 9A31 for the rear and running that for a little bit until I got an MLA module. But now I'm thinking of buying a high output alt and running my system with the yellow top for a little while until I could buy a 9A31. What do you guys think I should do? I only have enough money for one or the other. Thanks in advance and this is my first post here!