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.
i've heard of people having good results with some of the old school low mass arms and higher compliance cartridges on 160s like yours. mayware unipivot, grace 707, infinity black widow combined with things like a grado woodie or even the prestige grado stuff. makes sense to me in light of the suspended deck. stock rega's didn't work optimally on lp12s so i would reckon they are similar on 150/160s... ie, you can get them to work decent with the right cartridge, but not an optimal match. older SME arms work well on thorens suspended as well.
Linn arms are also a popular match. But the SME 3009 seem to be the most preferred.
i agree with all the arms named above. you may want to upgrade the cartridge first, before diving into this project. the sme is the 'classic' pairing that most enthusiasts like, but even the stock arm is finally getting a little respect 30 years later.
Thanks for the advice. I'll look into your suggestions. Plus, I already have a Grado woodie; platimun, I think.