Ive had both lips installed on my car and from my experience is that the Mugen style lip will hang alot lower than the type r. I think the Mugen lip will give you more than a 2cm drop closer to the ground from memory and will scrape if your car is lowered. Just get a Polyurethane lip and you wont have a problem with cracking as it just bends. On the other hand, the type r lip makes minimal difference in ground clearance once installed, but whatever you do, get a polyurethane lip no matter what

Also how much is your car is lowered and what size rims are you running on?