99 T45 in 97 - Speed Cal + tune or tune only?

[Attaus]

Just replaced the T45 in my 97 with the 99. I know the mount points are different I'm working on that but I was wondering if the Speed Cal is necessary or if the signal can be corrected with an SCT or DF tune? College student here so budget is tight, would rather not get both if I don't need them. Thanks

EDIT: The 97 speedo is mechanical, 99 is electrical. From the guy on here who created Speed Cal the sine wave is inverted.. it doesn't seem like I could only use the tune, but just thought I'd ask and try to save if I could.

 

[DHG4410]

I have a T45 tail section from a 97 if you need it. You will have to replace the speed O gear.

 

[Attaus]

I have a T45 tail section from a 97 if you need it. You will have to replace the speed O gear.

If I just swap the tail section and keep the gear from my old T45 that would work?

What's my cost?

 

[DHG4410]

I saw these things on ebay going for $150 but its laying around how about $80 shipped to your door.