I fly a TB20 and love it. If you offered me a TB20 or an SR22 I would choose the TB20 every time.
I would choose a TB10 over a TB9. Significant extra power. The TB9 is a fine plane, much nicer than the traditional spamcans you see everywhere, but a TB10 is significantly better.
Re IFR, you need to ask yourself whether you want to do "proper IFR" (with an IR, European touring) or "UK style IFR" (with an IMC Rating, popping in and out of clouds in Class G while dodging the base of the London TMA...). The equipment carriage requirements for the two are very different. Airways level equipment won't come cheap, especially if you also want to be legal
And it is usually cheaper to buy a plane with the required avionics already in, or mostly in, than to buy something cheaper, rip it all out (the stuff you rip out can barely be given away) and pay for new stuff.
I will send you a PM with more info.