mass air question

there is no need to up the fuel/air until you change the heads/cam/intake and even then it may not be necessary depending on what combo you go with.

^^^^ What he said
Leave well enough alone

Your 19lb injectors are good until at least 285 hp. As the others have said, adding a MAF and 24lbers isn't worth the hassle now. Also, larger injectors don't add HP, they simply support the amount oh HP you have.

I'll add that with the restrictive stock tb, intake and heads, you won't notice any difference with a larger MAF calibrated for the stock injectors. Since you already have the MAF and 24lb injectors, I would wait until you do a top end swap and then slap them on. I see you are talking about the TFS top end kit, which is a great HCI setup. Then it would make sense for the MAF and injectors.

If you are on a budget, a cheap but decent top end swap is to swap out an explorer intake, 65 mm tb, and heads. You won't make the same HP as the TFS kit, but the cost of the parts is maybe 3-400 bucks vs. 2500 for the TFS kit.

You should be capable now. Depending on the automatic. I would say lots of gain can be had with an AOD by adding a stall converter. Also a cheap GT40 intake would wake it up a little. Have fun.