i was thinking about putting an optima battery in my 99 5.3 silverado but didnt really want to pay that much if it didnt make a difference. also wanting any input on msd ignition or one like it to get more power out of the engine. any input on these or maybe some other options i could go without spending alot of money. thanks

 

In the world of automotive, money = more power
The optima battery will give you a more reliable power source to your engine and accessories not more engine power.
The MSD ignition will do the same provide reliable power to the ignition system but not more power out of the engine.

To get more power out of the engine you have to affect the ability of the engine to breathe effectively, better air flow in and out of the engine and its a combination of things.

K&N filter with cold air intake AND a cat back exhaust will provide some top end improvements.
Porting and polishing intake and exhaust systems will provide even greater gains.

Adding some of the items you mentioned also add to the "look" of the vehicle under the hood and have there own value.

Asking questions is the best way to find improvements that are cost effective and easy to do and you started that with this post!

 

Dont waste your money on the ignition it will not make a lick of difference. Like in2 said go cold air intake and exhaust- dual flowmaster will sound bad as well. I have the same engine and those did make a difference but not enough to justify the cost. The value for me was because I like how they looked and sounded as well but dont expect to be blown away by performance by adding them.