I don't know where people get that TB spacers only work at certain temps. They do, in fact, cool the intake charge a bit. If you are asking whether a spacer is a better investment than a header then the answer is a qualified "No." But if you are asking if a TB spacer is worth the money, I personally think so if you can get one for 30 or 40 bucks.

The spacer just increases the volume of the IM, basically, so it's not gonna interfere with your intake unless you just dont' have any more clearance for your intake. An actual bigger bore throttle body would be better, but some of them things can cost 300-400 bucks. Yeah, no thanks. LIke I said, find a used OEM that is bigger and will fit your IM. I got my 60mm for 10 bucks.

I vote for your parts in this order.

1. Cat-back
2. Header
3. Spacer
And then you can work on getting a bigger TB or even invest in a Skunk2 intake manifold.

 

personally...id get an intake after the header and put it on with the spacer.

 

I didn't put intake on there becasue I thought he already had an SRI.