Front & rear suspension mods can help the stock VMax frame, but it's obviously never gonna be a GSXR!
You already have the 43 mm downtubes, add RICOR valves and Progressive Suspension straight rate springs and a set of better rear shocks, a frame brace pair, a front fork brace, and radial tires via a new modded (17 or 18") rear wheel and two radial tires. A new frame is probably gonna run $3K. The mods mentioned will probably be about 1/2 that.
Remember this is a bike designed in the early 1980's so no way is it going to match-up to a modern bike. However, doing the mods mentioned will allow it to be much more fun than stock, and within operational parameters, you can surprise a great many riders who don't expect something 'that old' to behave in that fashion!
I think Harris will build anything you want, bring euro's.