Porting the intake is an overall waste of money unless it's going to compliment other mods such as forced induction and/or heads+cam work. It's pretty expensive for an extrude hone intake job and the benefits may not be worth the extra money. If staying stock, I say don't bother porting the intake.
With the intake off....consider getting it painted/powder coated a different color, valve covers too.
Also check your spark plug wires and replace them if necessary. Easier to get to the coil packs behind the intake with it removed. If upgrading spark plug wires consider AB's wires (QualityWires.com).
Check the condition of the CCV grommet on top of the block directly behind the T-stat housing. It's a rubber grommet that tees into the intake manifold under the TB's. Over time, these grommets can become brittle, crack and/or leak. Almost impossible to service with the intake installed.
Regarding the t-stat, in and of itself, a lower temp t-stat is not going to do much in helping your engine run cooler. Air flow is the biggest factor. Also, consider getting an SCT Flash tune, particularly one whereby the fan turn on/off temps are adjusted to come on lower. This in conjuction with the t-stat helps with cooler temps. Or consider this when you decide to tune your Viper down the road.
I had a 172 degree t-stat installed. Not very noticeable difference in operating temps until I did the tune with the fan settings and a vented cowl. Only once, during winter (35-40 degree weather) did I get a CEL which had something to do about the operating temp being too low. Tator chalked it up to the lowet t-stat and can throw a cell if you plan on driving your Viper in cold temperatures. There were no adverse effects from the CEL coming on.
If you don't have a service manual, you should find out the intake manifold bolt torque specs and torque sequence. The intake manifold gaskets are paper and will need to be replaced. You can get them from VPA and they're fairly inexpensive.
