I lready removed the old computer, any unneeded wiring, emisions, old vacum lines etc. will that be an issue then? i've already taken out anything that wasnt needed to run it as a carb setup. even a single wire alternator and dist. Is that going to make it hard to tie in the new system?
No, it won't make it hard to install at all.
However, suggest before you go the Howell route you consider what you are doing. Howell sells their kit as a complete system, essentially sourcing all the parts and pieces for you and combining it. What you will get is a GM ecm (the same one used in millions of gm installations from mid 80s to early 90s) throttle body MAP sensor, coolant temp sensor, O2 sensor, wiring harness and throttle body adapter, and with some kits you get a velocity speed sensor. the Howell system will control fuel only, not spark or ignition
What you end up with after install is an electronically controlled precisely metered fuel system, and you retain your old ignition and spark control (vacuum and mechanical advance systems). If you need an emissions legal tested system, such as in California, Howell provides that.
IMO, the real advantages of fuel injection are when you get precisely metered fuel and precisely controlled ignition spark. That way, your ecm monitors the changing engine conditions and adjusts both, spark and fuel, so you remain with the best operating system under any conditions. For reasons I don't understand, Howell removed the wires that control ignition form the harness and just doesn't use that feature, though it is an integral part of the gm ecm and system.
If you are reasonably handy and can follow simple guided instructions you can make your own system from parts and pieces you procure yourself individually and have a system that controls both spark and fuel for around $400. There are detailed write-ups on the board, I have a couple saved in word format, and there are plenty of folks here and at Binder Planet that can advise how to go about it. I chose that way over Howell and I've been very happy with my TBI system. I'm not knocking Howell cause they sell a good product, have gotten the approvals for EPA compliance, and seem to give decent customer service and advice. However, IMO, their product lacks a key feature and is pricey.
As for responsiveness and performance, the fuel injection will be much better than you have now. Starts under all weather conditions will be completely reliable, your mileage should be in the 17-18 around town if you keep your foot out of the accelerator, and the gas smells and constant tuning will go away.
To answer your question, the only old sensors you had on your jeep that could be used by Howell are the MAP sensor and O2 sensor (I think the temp sensor is also possible, but would have to look at the specs to make certain). Howell gives you new ones anyway.