I used to get those effects a lot. I can't get them anymore though. If I try to, I'll end up paranoid, feeling like I might snap, and objects will come to life and cry (or rarely jump up and down in joy). It's very different now than it once was.
As for the heart rate, I've gotten around 150bpm just by sitting around while really stoned. It feels like my heart is about to rip through my chest. Other times, I can hear it so clearly that it's like a giant house-sized drum. Sometimes I feel like I'm in a game or movie that I watched when I was a baby, or even a dream from that period. I've merged with a goddess and seen three-dimensional cross sections of objects, saw reality as a person in a gameshow, and have been in a dome where there were engines that ran the reality software for different people (I saw my own broken down one, too) and gods were criticizing me. I've also seen my house turn into a slaughterhouse that was trying to eat me and have seen reality being sucked into a black-hole-type thing.
Overdose on indica, and you'll feel really slow and fall asleep. Overdose on a good Sativa, and you'll trip like you're on a strong hallucinogen. I'd advise you to stay away from this though, it's a lot more psychosis-like than the classic psychedelics, so I'd recommend using those to trip. Personally, I rarely enjoy an intense experience on weed. I find that it's good for a high, not a trip. Also, if you have light highs every day (or every other day), you'll feel alright for a long time. If you trip out on it constantly, you'll probably feel destroyed within a year.