Just a small hint (what i first always forgot when using a tune from someone else)
match the power/pp first, always match the gearbox as the last action you do.
So step 0. match power/pp first.
I have the same problem with that tune, i just tried it again a few minutes ago.
I load up my database and this is how i got the gearbox matched.
View attachment 516551
So i first did a oilchange, then added rigidity to the body
got the pp matched to 627pp
tried the initial speed of 180mph (290kmh) and could not match the gears.
so changed initial speed to 240kmh/149mph and i could match the gears.
For me the important settings from
@shaunm80 are the suspension.
If the gearbox doesn't match, i try some stuff myself, mostly stock gearbox and increase or decrease the topspeed. ( and change LSD to my drivingstyle)
Of all the tunes from
@shaunm80 i believe i had two or max three tunes that didn't match the gearbox.
But thanks to those suspensions i had more and better traction in the seasonal races.
But
@RandyDale wrote
Start in reverse when you tune( do not start from top to bottom settings):
Oilchange needed in the tune? first thing you do before going into settings
Bodyparts? add them, do not add parts that are not in the tune, "flatfloor" adds pp, so don't add it when its not in the tune!
Settings:
1-Go to the bottom and start with body settings (add/remove weight, position the added weight(+ or -), downforce setting)
2-Add the power parts or set the power limiter or both.
3-Set the drivetrain (lsd, clutch/carbon axle,diff)
4- check if the pp matches the tune you want to use.
5- pp does not match? missing 7pp? you forgot the oilchange
More pp then in the tune? added a flatfloor, or powerpart, that doesn't belong? remove it or set powerlimit to match pp.
But it is better to remove the parts then use the powerlimiter to decrease for matching pp.
6- your pp ingame matches the tune? set your gearbox, it should match now
7- match the suspension and brake settings
8- if needed, buy the right tires
If the gearbox still did not match? check the power and bodyparts again and remove the unwanted ones.
Did you have to add weight/ballast? is it in the right position? moving the ballast also affects the pp.
Check if you really had to do an oilchange (oilchange mostly adds 7pp and can't be removed)
Still no matching gearbox? you used an old tune, or there's a little mistake from the tunecreator.
ps.
@RandyDale ?? how could you set 180kph?? minimal value is 240kph or 149mph for the nascar
@shaunm80 uses MPH miles per hour, not KPH kilometers per hour.
1Mile per hour is around 1,609344 Kilometer per hour.
only 2 gold are missing : Senna's Lotus at Brands Hatch and the Moon Coffee Break cone crap
.
It's just not fair!!! 
