A most have mentioned, the first thing to do is find out of the cam sprockets have been welded to the cams. This is a requirement and there is a good deal about it available here and at v8sho.com.
Past that, the car only has normal problems.
At your mileage, unless you have records about what was done for the transmission at 100K, you need to do that. The pan will have to be dropped to change the filter and the fluid changed.
As per modifications, some form of 'Porterization' is a good first step. This tosses away the air intake mess and draws cold air from the inner wheel well. It is a modification that you can do yourself or have done for you quickly, easily, and cheaply. I did mine for the cost of some truck rad hose and a few screws. Again, there should be info on this at v8sho.com
From there, most mods are dependent on what you are after. For handling you can do a good deal, though the starting point is already good, by adding a front strut tower brace, hardening up the subframe mounts, messsing about with the sway bars and wheel/tire combinations, etc. For sound you can play with the mufflers, cats, resonators, etc.
So, welcome.
pax, smn