Questions on Cage and harness

I have started taking my 97 Z28 to track days (road course), this year I upgrade the suspension, with Koni SA's, hotchkis springs, 35 mm sway bar and adj. panhard bar. I also add C5 brakes. After a few events I am realizing that I could really use a 5pt harness to hold me in because I'm always trying to brace myself for the corners. Is it worth adding a roll cage? 4pt or 6pt. I don't ever plan on seriously racing the car but I will be attending 3+ track days a year from now on. I like the idea of adding additional safety to the car because I do see 120+ on the track. Does it need to be a weld in or can I just use a bolt in? If I don't add a cage is there a way to still add a 5 pt harness? This car is not my daily driver, but I do take it to work and stuff a couple of times a week.

I have a 6 point Wolfe roll bar, bolt in. It ties to my Kenny Brown DD SFCs so it really stiffens up the chassis flex (good thing). Access in and out of the car is decent. Comes with mounting points for the top 2 straps. I fabricated a bar under the seat (connects to the front 2 seat bolts) for the crotch belt. I piggybacked the lap belt with the stock mounting points.