yep the PLP is the only one that will fit the is300 with no problems...ive heard mixed reports about JIC products, most of them negative
as for the differences in feeling..
well ive not driven The Monster with the PLP brace yet, as we are still doing the electrics, i did drive it as an is200 with the cusco and it was fantastic.....as the monster now has a supra engine, it would be unfair of me to even try and compare, as 1. i wouldnt drive it without a front brace,and 2. it wont have been driven with the cusco fitted with the supra engine fitted...plus with over 650bhp...the feeling of the brace will be the last thoughts on my mind