GaGa already came precoated structural by dipped galvanizing. The body by right can last 56 years without rust(if vapor goes under the sealant and turn the sealant acidic is another story, but still can easily last 10 ~ 20 years). However though, all car manufacturers only tells you they only expect rust free for 6 years. The muddy stuff you mentioned is called BITUMEN spray. It used to be 1 of those anti rust people use to coat the wheel arch. At 1st I thought Plotong cut cost go save up that section, now that I know it was being removed from most car manufacturer due to save weight as those coating can yield up to 10s of kilos depending on the thickness applied. Can be easily obtained from TESCO for less than RM10 sendiri sapu, cari dekat juai thinner/turpentine section.
http://youtu.be/po9zI_pOlRQ?t=4m13sAs for tinting, according to a friend in Plotong, the tint itself can void your powah windoe woranti ady

But hell, if interested may consult
DaBestOne. All my cars sent to him for tinting with reasonable price, superb quality. Best of all, some branches got hot chicks working

If not mistaken, basic tint full car RM180. Quality 1s, RM200/4window.
Voltage stabilizer/grounding kabel/ignition booster boley carik
Mahihi /
V12kompressor diorang ade buat. If you wait for me, you'll have to melayari
https://www.slowlywait.com.my 
I have opened my own shop,feel free to come and do service and maintenance if u think that putrajaya abit far,lol...it's in kota kemuning