First car finish

They should still go on ok. If you don't mind the difference in sheen, you can forego the clear coat.

What Jake???!!! A car?! ;)

Decals should stick to a gloss finish fine.  Problems come with use over matt finish.  Decals do not really need sealing, but  a clear coat helps with uniform sheen over both decals and paint.

If you do not seal in the decals with a too coat, and you plan on keeping the model for many years, the decals will eventually dry out and pull away from the surface. We are talking in the 10-20 year range. But it will most likely eventually happen. Especially in the climate of the area that we live in Jake.

Seeing that you've use Tamiya rattle cans up to now, I agree, stick to the same!

BUT... TS13 (Tamiya gloss clear rattle cans) can be notoriously difficult for some people and may "eat" decals. I have not had such problems (touching wood!) - BUT I tend to apply over other TS spray (you're safe there!) and thin layers usually helps.

However, I have not yet applied polish and either decal or clearcoat over that...

Carlos - what are YOU doing in cars!? I am giving this one to a friend who gave me the kit as a joke, so now the jokes on him. I already tired the license plate decals and they fell off some after drying so I coated them but I think a clear coat would be necessary to hold them. If not Tamiya TS13, do you think I can use Krylon Crystal Clear gloss?  

Do clear coat.

I don't like Krylon. It's cheap but you get what you pay for. It goes on pretty thick.

Jake I just had to chime in because I saw it was you. ;) I am not a car model guy as you well know. I have only completed one for me in the past 30+ years. But it does sound like the decals have an adhesive problem. In that case, a top coat is a must. I can't say anything for or against Krylon. But I would suggest my old favorite of Future. Or you can check with the car guys at IPMS Chapter meet in a couple weeks.

Thanks for the tip. I had not tried it. What would YOU recommend?  Carlos thinks Future and I think the car guys do use it?

Thanks for your time.   

Yeah, I have used the closest thing we have to Future over here (South Africa) to good effect... Don't know what you have as base colour, but mine was not over a metallic colour. And it was in small scale (43rd).