Adrifto

mr_mr2gt
..they couldn't fit a silencer on it because there was no room apparently.. 

 
I'm referring to the small cone type ones that just slide in to the exhaust tip, not a cut and weld job and fairly easily reversible.
 

I got ones simular to the above type, but the adjustable type, allowing you to open or close to min or max without need to remove the whole silencer. + it helps you find get the exact tone you are after.

If any of those six socket head cap bolts need to be replaced make sure they are very good quality. They must have the three load spreading washers installed and correctly torqued to spec. BGB tells the answer.
I then check them after about 300 km and paint mark them.
Right hand side is probably loose too.
Hope your dad is familiar with reassembling those CV joints. They are a bit of a trick to do correctly.
If it goes together easily you have it arse about face and it won't work.
Let us know how you get on with it.