You don't need a laptop to use the Tweecer. I've used my 5 year old computer with the software. And I don't see a need for replacing the chip either. Unless you want to spend another 500+ on replacing the hardware again at a later date, or you don't plan to tune it again, getting the PMS, the Tweecer, or any other piggyback system is advantageous because you can use them to change all of the parameters than an aftermarket chip will, but you can continue to change them with new modifications or if you just feel like tweaking the parameters.
Another cool aspect with the tweecer is that you can set differing tunes that can be toggled with the flip of a switch to account for running nitrous, n/a, valet switch etc...
Just my 2 cents,
Chris