I have a genuine 2008 Rev 3 but would like to try some mods to improve it. Any ideas please

 The `08 was a very good machine as is, just ride it a lot. Other wise sell it and buy an Evo.

As mentioned above, modification isn't going to help it.  If you have the urge to tinker then get a stock TY175 that's been "restored" by someone who doesn't know what they're doing, and then turn it into a competition worthy modernised Majesty to your own personal taste ... it'll keep you busy and your bank account empty, ask me how I know

As above except probably just little tweaks like swapping screws on rear mud guard for tiny cable ties so it's less likely to snap if you drop it, fitting a mud flap to front so it doesn't clog the radiator, fit a lanyard switch. Also the famous clutch mod (see forum). Get some new tyres and enjoy it!