One thing you are talking about doing is ,removing or gutting the cat.
The minute you do that you are going to have to deal with the stink from the exhaust,it turns your nice daily driver into a smelly somewhat obnoxious beast.
where you are just going for a high 12 or low 13 second "driver", I would suggest getting rid of the old cat (depending on condition)which may be semi clogged anyway and install a new high flow cat on it,technology has come along way and a new technology, high flow cat will cost you very little power on a let's say 12.8 - 13.0 car, but will make it a much nicer car to be around without all the exhaust stink of a catless car.
Just a couple times of being around a running non catted car for a few mins and then walking in the house smelling like raw fuel/exhaust and you will see what i mean.
That smell just seems to stay in your nostrils and stuck to your clothes and hair for a long time.
Couple that with the smell of the inevitable oil being dripped on hot surfaces, from all the usual oil leaks from these cars,and the smell will start to make you not like your new found toy so much.
Almost without fail when i buy a tr, I have to immediatly attack the oil leaks, and then also install a new cat because the old one was removed and stinks.(probably the reason the car was sold in the first place, it stunk too much)
Even my last big power vehicle, a 650 hp supercharged v8 had 2 high flow cats on it.
The aftermarket cats are pretty cheap and will make your car much more driver friendly.
I would do your other mods first, and see if you get to your desired power level then decide if you need to free up the exhaust .
Ps ,The biggest power making trick with these cars is called ((( ALKY INJECTION ))) .
Without it you would not be seeing all these 10 and 11 second pump gas cars.
I think just beefing up your fuel system with all the above mentioned suggestions,(pump,injectors,hotwire,adjustable fpr,etc) and a few incidentals(scanmaster,tt chip etc.) and adding alky control and turning up the boost puts you right into your high 12 - low 13 second range, maybe better. Of course having a guru tune it will produce best results .
good luck.