With that many miles you you could be running a pretty good chance of a parts failure of some sort.
If the IP or lift pump has never been upgraded, there's a good chance that the IP could/would fail. Maybe, maybe not, it's just kind of a crap shoot with the VP44.
The tranny might hold, it might not, depends on what levels you run the Comp on most of the time.
My suggestion would be to get a pyro, boost and FP gauge and maybe even a trans temp gauge to check engine and trans vitals before you go adding power.
It's not as much fun to do the important stuff first, but it can be less costly in the long run.
You can put the Comp on and if everything works fine, then great, but if the VP44 craps out due to a non working lift pump or internal IP failure, then you're out $1k-2k for a lift pump and VP44. If the tranny goes out then you're probably looking at $1500-2000 for just a TC and VB (assuming you have an auto).
On the other hand, you might be OK. These are just some examples of possible failures.