I'm looking to get a new stem for my bike along with new handle bars. I have an 07 Redline 925 I believe (its the gray one). I bought it used and has a specialized stem installed and I'd like to replace it, but I'm unsure of the what I need to know in terms its sizing along with the headset. I've looked at some other model specs and they say 1 1/8. Does anyone have exact specs?

It's 1 1/8" threadless. They only other spec you'd need would be stack height, but that's only if you have the stem completely slammed (no spacers).

And length.

I have two spacers so do I just measure them?

There are two numbers on the stem (+16 +8) would that be the length?

I didn't think about length because I'm assuming he wants to replace it due to length or angle.

OP, if you're using spacers, that doesn't matter.

I'm mainly looking to get one with a higher angle because I feel as if my body leans forward too much with the current installed one.

Check your LBS for something like this:

https://www.origin-8.com/?page_id=91&short_code=Pro+Pulsion+Riser+ATB+Stem&cl1=STEMS

Comes in 35 and 40 degree rise (that's the angle at which it points upwards).

Looks pricey how much does it go for?

Should be about $30 at a shop, or $20+ online.