What do you all recommend for a BPU+ car as far as a blow off valve that will not take away any power? I like the sound and know I need to keep the stock one in place. I like the sound of most of them.'
If keeping the stock BOV is a major concern and you don't want hardpipes, then your main option is the Blitz Kit. It replaces the intercooler pipe that leads into the intake manifold. It's a hardpipe with the Blitz BOV attached.
Your other options are getting HKS hardpipes and having a BOV welded onto one of your IC pipes. Or, if you have an FMIC and then you can weld it on the turbo side of the FMIC pipes.
I run the HKS SSBOV in the stock location and love it.
I'm also running the HKS SSBOV in the stock location and am very happy with it. I would pretty much stick to either the HKS or the Blitz. The HKS is technically a little better at high boost levels but for our usage it mostly comes down to sound preference.
another option of keeping the stock bov is getting the apexi. the kit is very inexpensive, and comes with the hardpipe that goes into the throttle body and the bov bolts right on it. i used to have it and had no problems with it leaking like some people have, you just have to adj. it right. your best bet would be to get some hardpipes or a fmic with hardpipes and get an hks bov and flange, hks has the best design as far as not leaking at all. this way you can run it in conjunction with your stock bov, i went this way for a while and loved it.