Upgrade tonearm on Thorens TD 160?

Is is worth upgrading from the stock tonearm on a vintage Thorens TD160? I've tweaked it about all I can - replaced pressboard base with birch ply, added BRD cones as feet, Dynamat on sub chassis, plinth and sub platter and added RCA jacks to replace hardwired tonearm cables. I must say it blew the socks off of my MMF5 which I subsequently sold.

Now the question: is it possible to DYI upgrade the tonearm? Is there a moderate-priced arm to do this with? e.g. Rega RB 250 0r 300? Would such an upgrade yield any improvement and if so just what improvement would I notice? And, finally, How would I go about doing it? That is, how would I address/learn-how-to fit the arm onto the plinth and any necessary modifications.

I'd prefer to do this myself but would need guidance.

Thanks for any advice.